2004-10-31

 

USGS Update 2004-0ct-31 10:00

Current Update

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift southeastward from the volcano.

Seismicity remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.

Crews did not go the field yesterday because of inclement weather. No field work is planned for today.



2004-10-30

 

USGS Update 2004-0ct-30 10:00

Current Update

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift eastward from the volcano.

Seismicity remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.

The new GPS station on the southern part of the new dome (uplifted glacial ice, rock debris, and new lava) shows continued southward motion—about 10 m since October 28; a station near the summit of the old dome shows continued slow northward motion.

Crews did not go the field yesterday because of inclement weather. No field work is planned for today for the same reason.



2004-10-29

 

USGS Update 2004-0ct-29 10:00

Current Update

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift south to southeastward from the volcano.

Seismicity remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.

The new GPS station on the southern part of the new dome (uplifted glacial ice, rock debris, and new lava) shows continued southward motion—about 6 m in the past 36 hours; a station near the summit of the old dome shows continued slow northward motion. GPS, LIDAR, and photogrammetric measurements, in combination with visual observations over recent days suggest that the dome complex is spreading outward at its margins similarly to the expected behavior of a viscous lava flow.

Crews did not go the field yesterday because of inclement weather. No field work is planned for today for the same reason.



 

Latest Updates



2004-10-28

 

USGS Update 2004-0ct-28 10:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift southward from the volcano.

Seismicity remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.

Preliminary reduction of LIDAR data from October 14 indicates that the volume increase of the new dome (uplifted glacial ice, rock debris, and new lava) was approximately 11 million cubic meters at that time, giving a growth rate of about 7 cubic meters per second.

Crews had a productive day in the field yesterday. Work included installation of two new GPS stations to measure ground deformation on the surface of the growing dome, geologic observations and sampling, collection of oblique stereophotos for tracking growth of the new dome, thermal-infrared mapping to determine temperature distribution in the new and old (1980-86) domes, a gas-measurement flight, and telemetry maintenance. Results include the following: the new GPS station on the southern part of the new dome shows motion downward and to the southeast; a station near the summit of the old dome has moved northward about 7 cm since October 20; thermal imaging showed an elongate band of elevated surface temperature, locally as great as 775º C along the west face of the new dome coincident with the area of exposed newly extruded lava; gas-emission rates measured yesterday are similar to recent previous measurements (SO2 about 250 tons per day, CO2 about 300 tons per day, H2S about 2 tons per day); samples of dome rock similar in appearance to the rock of the older dome were collected from two localities in the vicinity of the exposed new lava. In the aggregate, the above results indicate that the character and rise of magma is continuing as it has over tha past few weeks. The visible steam plume is caused by condensation of moisture in the cold air above the hot dome.

No field work is planned for today.



 

Latest Updates



2004-10-27

 

USGS Update 2004-0ct-27 10:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift southwest from the volcano.

Seismicity remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.

Samples of the new dacite lava collected on 20 October are mostly similar chemically and texturally to lava erupted during the late period of dome growth in the 1980’s (1984-1986). This is consistent with slow rise, degassing, and cooling of magma within the volcano’s conduit. However, a minor component of the 10/20/04 sample has textures and mineral compositions indicative of rapid ascent of magma from a region at greater depth and greater temperature (900º C).

Crews did not go to the field yesterday, but field work including geologic and thermal-imaging observations, a gas-measurement flight, and telemetry maintenance is under way.



2004-10-26

 

USGS Update 2004-0ct-26 10:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift north to northwestward from the volcano.

Seismicity remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.

Crews did not go to the field yesterday, but field work is planned for tomorrow and Thursday if the weather improves.



2004-10-25

 

USGS Update 2004-0ct-25 10:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift northeastward from the volcano.

Seismicity remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.

Yesterday field crews were able to make brief geological and thermal-imaging observations and to install an additional GPS receiver. Thick steam clouds obscured much of the new lava dome, but some changes were apparent since the last observations on 21 October. A small apron of warm ash and blocks that fell from the dome lies on newly fallen snow on its west side and a small stream of melt water flows from a nearby area of intensely deformed glacier ice. A new GPS instrument was slung by helicopter and placed on a large boulder just north of the 1980-86 lava dome. It will aid in detecting any crater-wide deformation. Initial analyses were made over the weekend of samples of the new lava dome that were collected on 20 October. They show that, since lava first appeared on 11 October, it has been rising more easily from depth and not spending much more than a few days at shallow levels before being extruded onto the surface. Reviews of several lines of evidence confirm that the average rate of volume change between late September and mid-October of the deformed area and new lava dome was about 8 cubic meters (10 cubic yards, or a typical dump truck full) per second. A substantial part of that change must be magma, which suggests a rate similar to that of many other lava-dome-building eruptions.



2004-10-24

 

Latest Updates



 

USGS Update 2004-0ct-24 11:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift southeastward to eastward from the volcano.

Seismicity remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.

No field work was possible yesterday owing to poor weather. Today field crews will attempt to make geological and thermal-imaging observations and to take aerial photographs for use in estimating the rate of growth of the new lava dome and the deforming area.



2004-10-23

 

USGS Update 2004-0ct-23 11:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift eastward from the volcano. Seismicity remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.

No geological or thermal-imaging observations were possible yesterday owing to poor weather. No field work is planned for today, but missions are being planned for Sunday.



2004-10-22

 

USGS Update 2004-0ct-22 10:10

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift eastward from the volcano.

Seismicity remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.

In spite of deteriorating weather conditions yesterday, geological and thermal-imaging observations were possible and indicated that both the area of uplift and the new lava extrusion have grown noticeably since viewed on the previous day. The area of uplift and intense deformation continues to move southward and is nearing the crater wall. Intense steaming prohibited detailed estimates of dimensions, but the new lava extrusion, which has a volume of about 2 million cubic yards, displayed a new protrusion that had a maximum temperature of about 650 degrees C (1200 degrees F).

Any field work today will be limited to maintenance of telemetry systems.



2004-10-21

 

USGS Update 2004-0ct-21 10:45

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift southeastward from the volcano.

In the past 24 hours, seismicity has decreased somewhat and remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. Last night, glow from this new lava was intermittently visible on the U.S. Forest Service web camera. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor.

Yesterday was a busy day in the field. Geological and thermal-imaging observations confirmed that both the area of uplift and the new lava extrusion have increased in size noticeably since last seen on October 14. The area of uplift and intense deformation continues to move southward and is nearing the crater wall. About 1 foot of new snow with a light dusting of ash covers much of the uplift, except for the new lava extrusion, which is steaming heavily. The new lava extrusion, which occupies the western part of the uplift, is now about 900 ft long by 250 ft wide and 230 ft high and has a volume of almost 2 million cubic yards. Its maximum temperature is about 600 degrees C (1100 degrees F). Rock samples from the new lava extrusion were collected from a helicopter by using a bucket slung on a 100-ft line. The samples look like typical Mount St. Helens lava, called dacite. Further detailed analyses of the samples will help to answer questions about the character of the magma driving the eruption and how it relates to lava erupted in the 1980s.

A gas-sensing flight detected low levels of the volcanic gases carbon dioxide, sulfur dioxide, and hydrogen sulfide, which is consistent magma continuing to rise from depth.

Test flights of the Unmanned Aerial Vehicles (UAVs), which will hopefully be used for monitoring the crater area in the future, were conducted yesterday close to the Johnston Ridge Observatory. More tests are scheduled for today if weather conditions permit.

Field crews will attempt to obtain additional geological and thermal-imaging observations today. Other work will continue on maintenance of instrumentation and improving our telemetry systems.



2004-10-20

 

Latest Updates



 

USGS Update 2004-0ct-20 11:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift to the west and southwest from the volcano.

In the past 24 hours, seismicity has decreased somewhat and remains at a low level compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding a surface extrusion of lava. Last night, glow from this new lava was intermittently visible on the U.S. Forest Service web camera. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor.

Poor weather yesterday again prevented geological observations. When last seen during an overflight on October 14, estimated dimensions of the new lava extrusion were approximately 110 x 70 meters (360 x 230 ft) in length and height and about 18 m (58 ft) in width. The maximum temperature recorded on October 14 during the last successful overflight of the crater area, was 761 degrees C (1400 degrees F).

Today, weather conditions have improved considerably and field crews are flying this morning to obtain new photographs, video, thermal images, and other data. Preliminary reports from the field indicate that the new lava dome has increased in width since October 14 and much of the fin-shaped lava spine described earlier has collapsed. Some ash likely related to small avalanches from the spine and possibly small ash emissions is visible on snow inside the crater. A vigorous steam plume is rising to approximately 10,000 feet above sea level.

A gas measurement flight is planned for later in the day. Other field crews are conducting maintenance on instrumentation and improving our telemetry systems.



2004-10-19

 

USGS Update 2004-0ct-19 10:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky. Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift to the northwest, north, and northeast from the volcano.

In the past 24 hours, seismicity has not changed significantly and remains at a low level overall. Continuing storm noise explains some of the higher background signal observed. We have no new Global Positioning System (GPS) measurements to report. Poor weather yesterday again prevented geological observations.

The current level and character of seismicity are consistent with a continuing rise of magma driving uplift of the crater floor and feeding the surface extrusion of lava. Low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor.

When weather conditions improve, we will continue geologic observations, thermal imaging, and making improvements in telemetry systems.



2004-10-18

 

Latest Updates



 

USGS Update 2004-0ct-18 11:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. At this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky. Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift to the east and then to the north and northeast later this afternoon.

Seismicity has not changed significantly and remains at a low level overall. Continuing storm noise explains some of the higher background signal observed. We have no new Global Positioning System (GPS) measurements to report. Poor weather yesterday prevented geological observations.

The current level and character of seismicity are consistent with a continuing rise of magma driving uplift of the crater floor and feeding the surface extrusion of lava. Low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor. When weather conditions improve, we will continue geologic observations, thermal imaging, and making improvements in telemetry systems.



2004-10-17

 

USGS Update 2004-0ct-17 10:45

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Under current conditions, small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if they are triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. Such lahars pose negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people along the river channel upstream of the SRS. Owing to weather and stream-flow conditions at this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky. Although considered less likely at this time, eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that any ash clouds that rise above the crater rim today will drift northeastward to eastward later in the day.

Seismicity has increased slightly in the past 24 hours, but remains at a low level overall. Some of the higher seismicity is due to storm noise. Overnight, rainfall triggered a small debris flow that flowed north from the crater and changed rapidly to muddy streamflow within 5 km of the volcano. Global Positioning System (GPS) measurements continue to indicate only minor deformation of the northern part of the 1980-86 lava dome and no deformation of the outer flanks of the volcano. Poor weather yesterday prevented geological observations.

The current level and character of seismicity are consistent with a continuing rise of magma driving uplift of the crater floor and feeding the surface extrusion of lava. Low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor.

Field crews will not be out in today's poor weather. When weather conditions improve, we will continue geologic observations, thermal imaging, and making improvements in telemetry systems.



2004-10-16

 

Latest Updates



 

USGS Update 2004-0ct-16 11:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Under current conditions, small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if they are triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. Such lahars pose negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people working or recreating along the river channel upstream of the SRS. Furthermore, due to weather and stream-flow conditions at this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky. Although considered less likely at this time, eruptive activity could also evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that any ash clouds that rise above the crater rim today will drift east-southeastward to eastward later in the day.

During the past 24 hours, seismicity has remained at a low level. Global Positioning System (GPS) measurements continue to indicate only minor deformation of the northern part of the 1980-86 lava dome and no deformation of the outer flanks of the volcano. Poor weather yesterday limited geological observations to a few time-lapse pictures from the video camera at Sugar Bowl and brief views from Johnston Ridge Observatory. Parts of the area of uplift and new lava dome visible from those points were higher than when last seen on 14 October.

Our recent observations are consistent with ongoing rise of magma driving the uplift and feeding the surface extrusion of lava. Low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor.

Today, field crews will continue geologic observations, thermal imaging, and improvements in telemetry systems if weather conditions permit.



2004-10-15

 

USGS Update 2004-0ct-15 11:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months. Increase in the intensity of eruption could occur suddenly or with very little warning and may include explosive events that produce hazardous conditions within several miles of the volcano. Under current conditions, small lahars (volcanic debris flows) could suddenly descend the Toutle River valley if they are triggered by heavy rain or by interaction of hot rocks with snow or glacier ice. Such lahars pose negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people working or recreating along the river channel upstream of the SRS. Furthermore, due to weather and stream-flow conditions at this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky. Although considered less likely at this time, eruptive activity could also evolve into a more explosive phase that affects areas farther from the volcano and sends significant ash thousands of feet above the crater where it could be a hazard to aircraft and to downwind communities.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that any ash clouds that rise above the crater rim today will drift southeastward.

During the past 24 hours, seismicity has remained at a low level. Global Positioning System (GPS) measurements continue to indicate only minor deformation of the northern part of the 1980-86 lava dome and no deformation of the outer flanks of the volcano. A gas-sensing flight yesterday found conditions unchanged from Wednesday with a low flux of sulfur dioxide and no detectable carbon dioxide or hydrogen sulfide. Yesterday’s geological observations and thermal imaging of the new lava dome indicate continued slow extrusion of lava. In addition, the surrounding uplifting and intensely deforming area on the south side of the 1980-86 lava dome and adjoining glacier continues to broaden.

Our recent observations are consistent with ongoing rise of magma driving the uplift and feeding the surface extrusion of lava. Low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor.

Today, field crews will continue geologic observations, thermal imaging, and improvements in telemetry systems.

We continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.



 

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2004-10-14

 

USGS Update 2004-0ct-14 18:15

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity remained at a low level today. Today’s visual observations and thermal imaging of the crater were focused on the intensely deforming and uplifting area on the south side of the 1980-86 lava dome and the new lobe of lava in the western part of that area. The area of both the uplift and the new lobe of lava have increased slightly since yesterday. Yesterday’s gas-sensing flight detected low levels of sulfur dioxide and hydrogen sulfide, but no carbon dioxide. Abundant steam continues to rise from the area of lava extrusion to the crater rim, from which it is being dispersed downwind. Measurements taken yesterday of flow-rate and temperature in streams draining the crater showed no significant change from late September values.

Other field work today included a gas-sensing flight (data not yet reduced), downloading GPS data, and servicing GPS stations.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show that any ash clouds will drift south-southeastward this evening and southeastward tomorrow morning. Magma continues to be at a very shallow level and is extruding onto the surface and forming a new lobe of the lava dome. Small emissions of steam and ash are possible. Reflection onto steam clouds of incandescence or glow from the hot rock and gases will be visible at night from some locations.

Lava-dome growth is a dynamic process and, as we observed in the mid-1980s, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of activity over periods of days to weeks, or even months. We expect fluctuations in the level of eruptive activity to continue. Escalation could occur suddenly. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

Under current conditions, small lahars (volcanic debris flows) could be triggered if hot material from the new lava extrusion swiftly melts glacier ice. Such lahars pose negligible hazard below the Sediment Retention Structure (SRS), but could pose a hazard to people working or recreating along the river channel upstream of the SRS. Furthermore, due to weather and stream-flow conditions at this time of year, it is not unusual for rivers draining the volcano to contain high concentrations of sediment that turn the water murky.

There will no longer be daily media briefings at the Headquarters of the Gifford Pinchot National Forest. A media briefing will be held tomorrow at 1 p.m. at Castle Lake Viewpoint in the Mount St. Helens National Volcanic Monument. However no additional such briefing are planned until conditions warrant them. Beginning tomorrow, we will release only one daily update, at approximately 11 a.m. Tomorrow’s update will contain information regarding media contacts with the Joint Information Center.



 

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USGS Update 2004-0ct-14 07:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity remained at a low level overnight, little changed from yesterday. Wednesday's visual observations and thermal imaging of the crater focused on the intensely deforming and uplifting area on the south side of the 1980-86 lava dome and on the new lobe of lava in the western part of that area. The areas of both the uplift and the new lobe of lava are still increasing. Temperatures of almost 700 degrees C were measured in parts of the new lobe, from which ash-rich jets rose tens of meters. Abundant steam continued to rise from the area of lava extrusion to the crater rim, where it dispersed southwestward in strong winds.

Other field work on Wednesday included a gas-sensing flight (data not yet reduced), downloading GPS data, and observations of water flows and temperatures in streams draining the crater. Today's fieldwork will include a thermal imaging flight, geologic observations, and instrument maintenance.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show light north to northwesterly winds this morning. Any ash clouds will drift generally south to southeastward.

Magma continues to be at a very shallow level and is extruding onto the surface and forming a new lobe of the lava dome. Incandescence or glow from the hot rock will likely be visible intermittently from north of the volcano, or possibly from other vantage points if the right cloud conditions exist.

Lava-dome growth is a dynamic process and, as we observed in the mid-1980s, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of activity over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of eruptive activity to continue. Escalation could occur suddenly or with very little warning and may include explosive events. We continue therefore to monitor the situation closely and will issue additional updates and changes in alert level as warranted.



2004-10-13

 

USGS Update 2004-0ct-13 18:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity remained at a low level today, maintaining the slight increase that occurred last night. This morning’s visual observations and thermal imaging of the crater were focused on the intensely deforming and uplifting area on the south side of the 1980-86 lava dome and the new lobe of lava in the western part of that area. The area of both the uplift and the new lobe of lava have increased slightly since yesterday. Temperatures of almost 700 degrees C were measured in parts of the new lobe, from which ash-rich jets rose tens of meters. Abundant steam continued to rise from the area of lava extrusion to the crater rim, from which it was dispersed southwestward by strong winds.

Other field work today included a gas-sensing flight (data not yet reduced), downloading GPS data, and observations of water flows and temperatures in streams draining the crater.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show variable wind directions tonight, but generally northerly. Any ash clouds will drift southward this evening and southeastward tomorrow morning.

Magma continues to be at a very shallow level and is extruding onto the surface and forming a new lobe of the lava dome. Incandescence or glow from the hot rock will likely be visible intermittently from north of the volcano, or possibly from other vantage points if the right cloud conditions exist.

Lava-dome growth is a dynamic process and, as we observed in the mid-1980s, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of activity over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of eruptive activity to continue. Escalation could occur suddenly or with very little warning. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.



 

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USGS Update 2004-0ct-13 07:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity remained at a low, but slightly increasing level overnight. Yesterday’s visual observations and thermal imaging of the 1980-86 lava dome, the intensely deforming and uplifting area on the south side of the dome, and the new lava extrusion first seen on October 11 were hampered by steam clouds. Conditions appeared similar to those of October 11, with high temperatures (up to 600 degrees C) around the fin-shaped lava extrusion in the western part of the uplift. The area of high temperature appears to have increased in size. Abundant steam continued to rise from the fin area to the crater rim, from which it was dispersed southeastward by strong winds.

A new instrument array was lowered onto the uplifting area on October 12 by helicopter. It contains telemetered seismic, GPS, and tilt instruments, as well as a microphone. It will provide critical information on rate of movement of the uplift as well as a close-in seismic station, which is proving useful in interpreting very small seismic events that do not appear at more distant stations. Today, field crews will take new thermal images of the crater floor and dome, make gas-sensing measurements, perform routine maintenance of GPS sites, and take hydrological measurements.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show generally northerly winds. Any ash clouds will drift southward to southeastward.

As a result of the intense unrest of the past two and one-half weeks and recent observations, we infer that magma is at a very shallow level and is extruding onto the surface. Incandescence from hot rock or gases reflects off steam clouds and is visible from north of the volcano. During times of unrest, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of unrest over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of unrest to continue during coming days. Escalation in the degree of unrest could occur suddenly or with very little warning. There may be little time to raise the alert level before a hazardous event occurs. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.



2004-10-12

 

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USGS Update 2004-0ct-12 17:45

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity remained at a low, but gradually increasing level today. This morning’s visual observations and thermal imaging of the 1980-86 lava dome, the intensely deforming and uplifting area on the south side of the dome, and the new lava extrusion first seen yesterday afternoon were hampered by steam clouds. Conditions appeared similar to those of yesterday afternoon, with high temperatures (up to 600 degrees C) around the fin-shaped lava extrusion in the western part of the uplift. The area of high temperature appears to have increased in size. Abundant steam continued to rise from the fin area to the crater rim, from which it was dispersed southeastward by strong winds.

A new instrument array was lowered onto the uplifting area this afternoon by helicopter. It contains telemetered seismic, GPS, and tilt instruments, as well as a microphone. It will provide critical information on rate of movement of the uplift as well as a close-in seismic station. Other field work concentrated on improving satellite and radio telemetry systems.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show variable wind directions tonight, but generally northerly. Any ash clouds will drift southwestward to southeastward.

As a result of the intense unrest of the past two and one-half weeks and recent observations, we infer that magma is at a very shallow level and is likely extruding onto the surface. As last night, incandescence from hot rock or gases could reflect off steam clouds and be visible from north of the volcano. During times of unrest, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of unrest over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of unrest to continue during coming days. Escalation in the degree of unrest could occur suddenly or with very little warning. There may be little time to raise the alert level before a hazardous event occurs. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.



 

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USGS Update 2004-0ct-12 07:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity remained at a low level overnight. Small earthquakes (maximum about magnitude 1) continue to occur at a rate of about 1 per 5 to 10 minutes. Visual observations and thermal imaging of the crater, the 1980-86 lava dome, and the intensely deforming and uplifting area on the south side of the dome were made yesterday afternoon. Thermal imaging of the western part of the uplifting area revealed temperatures of 500 to 600 degrees C on a large pinkish-gray fin of rock and in nearby fumaroles and cracks. These observations are consistent with new lava having reached the surface of the uplift. Additional visual and thermal observations will be made today to further evaluate this interpretation.

A gas-sensing flight yesterday measured fluxes of sulfur dioxide and carbon dioxide that are similar to or slightly smaller than those measured on 7 October. The next gas-sensing flight is scheduled for tomorrow.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show winds this morning will remain northwesterly. Any ash clouds will drift south-southeastwardly to southeastwardly.

As a result of the intense unrest of the past two weeks and yesterday’s observations, we infer that magma is at a very shallow level, and perhaps at the surface. During times of unrest, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of unrest over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of unrest to continue during coming days. Escalation in the degree of unrest could occur suddenly or with very little warning. There may be little time to raise the alert level before a hazardous event occurs. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.



2004-10-11

 

USGS Update 2004-0ct-11 17:30

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity remained at a low level today. Currently small earthquakes (maximum about magnitude 1) are occurring at a rate of about 1 per 5 to 10 minutes. Visual observations and thermal imaging of the crater, the 1980-86 lava dome, and the intensely deforming and uplifting area on the south side of the dome were made during the afternoon. The western part of the uplifting area appears to be the most actively deforming site and was the source of a brief steam and emission about 16:00 that drifted southeastward. A dusting of ash on new snow in that sector suggests that similar minor ash emissions also occurred last night. A steam plume originating on the deforming area continues to rise above the crater rim and drift to the southeast. Scientists also conducted a gas-sensing flight. Results will be available tomorrow as will results of thermal imaging.

As a result of the intense unrest of the past two weeks, we infer that magma is at a very shallow level. During times of unrest, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of unrest over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of unrest to continue during coming days. Escalation in the degree of unrest and perhaps an eruption could occur suddenly or with very little warning. There may be little time to raise the alert level before a hazardous event occurs. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show winds this evening will remain northwesterly. Any ash clouds will drift south-southeastwardly to southeastwardly.



 

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USGS Update 2004-0ct-11 07:45

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismicity overnight remained at a low level similar to October 10. Small earthquakes (about magnitude 1) have continued at a rate of about 1 per 5 to 10 minutes.

Viewing conditions were very clear most of October 10, and fresh snow had fallen to the level of the crater floor north of the dome. A USGS field crew noticed a thin ash deposit on the snow in the crater and just beyond the crater rim, trending southeast from the active area.

A steam plume rose to crater rim level or slightly above all day on October 10, heading to the southeast. USGS field workers described the plume as “lazy”—no gas thrust or notably vigorous convection was observed. The plume was clean, with no noticeable ash or blue/orange haze. The odor of H2S was noted at the crater breach, but not elsewhere.

Helicopter field crews were at work on Sunday October 10. A telemetered webcam was placed at Sugarbowl and GPS data were downloaded.

The thermal imaging crew made an excellent video of the uplifted area of the south crater floor. The western portion of the the uplift was steaming over a large diffuse area. Maximum measured surface temperatures were 200-300 deg. C. The thermal imaging crew judged the uplifted area to have grown since it was last seen on the 7th.

No gas observations were made on October 10.

Rockfall deposits were not seen on or around the uplifted area, perhaps indicating a lull in its growth or deformation.

As a result of the intense unrest of the past 18 days, we infer that magma is at a very shallow level. During times of unrest, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of unrest over periods of days to weeks, oreven months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of unrest to continue during coming days. Escalation in the degree of unrest and perhaps an eruption could occur suddenly or with very little warning. There may be little time to raise the alert level before a hazardous event occurs. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

The weather forecast for the next several days is favorable for fieldwork and observations. Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show winds today will remain north-northwesterly. Any ash clouds will drift south- southeastwardly to southeastwardly.



2004-10-10

 

USGS Update 2004-0ct-10 17:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity remained at a low level today. Currently small earthquakes (about magnitude 1) are occurring at a rate of about 1 per 5 to 10 minutes. Very small earthquakes are occurring at a rate of about 1 per minute. Visual observations and thermal imaging of the crater, the 1980-86 lava dome, and the intensely deforming and uplifting area on the south side of the dome were made during the early afternoon. The deforming area has increased in area by about 10 percent since last seen on 7 October. Estimate of change in height awaits further analysis. A steam plume originating at vents on the deforming area is rising above the crater rim and drifting to the southeast. A dusting of ash on new snow high on the volcano suggests that minor ash emission may be occurring intermittently. Installation of a remotely controlled video camera provided by the USGS Hawaiian Volcano Observatory began late in the day at Sugar Bowl, which lies at the eastern side of The Breach, the open north end of the 1980 Crater.

As a result of the intense unrest of the past 11 days, we infer that magma is at a very shallow level. During times of unrest, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of unrest over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of unrest to continue during coming days. Escalation in the degree of unrest and perhaps an eruption could occur suddenly or with very little warning. There may be little time to raise the alert level before a hazardous event occurs. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show winds early this evening will remain northwesterly. Any ash clouds will drift south-southeastwardly to southeastwardly.



 

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USGS Update 2004-0ct-10 07:00

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity has decreased slightly over the past 20 hours to low levels, similar to those observed during the evening hours of October 7. Earthquakes continue to occur at a rate of about 1 per minute, but most have magnitudes of 1.0 or less. With the improving weather, a gas measuring flight is planned within the next two days.

Additional analysis of lidar and photographs of the intensely uplifting area on the south side of the lava dome suggests that the total volume change represented by the deformation between late September and October 6 is about 16 million cubic meters (21 million cubic yards). The average rate of change is about 2 million cubic meters per day (2.6 million cubic yards per day). If this figure represents the rate of intrusion of magma into shallow levels of the dome and(or) underlying crater floor, it is an intrusion rate about twice that measured during dome-building eruptions at Mount St. Helens in the 1980s. Cartographers with the USGS office in Denver are working to develop precise volume change estimates for the uplifted area from stereo airphotos acquired between 1 and 5 October.

As a result of the intense unrest of the past 17 days, we infer that magma is at a very shallow level. During times of unrest, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of unrest over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of unrest to continue during coming days. Escalation in the degree of unrest and perhaps an eruption could occur suddenly or with very little warning. There may be little time to raise the alert level before a hazardous event occurs. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show winds early this morning will be from the north-northwest. Any ash clouds will drift to the south-southeast.



2004-10-09

 

USGS Update 2004-0ct-09 17:30

Current Update

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity has remained at a moderate, but variable rate. Currently earthquakes up to magnitude 2 are occurring at a rate of about 1 every two to three minutes minutes. No visual observations of the crater, the 1980-86 lava dome, or the intensely deforming and uplifting area on the south side of the dome were possible today due to low clouds. No scientists worked in the field today.

Additional analysis of lidar and photographs of the intensely uplifting area on the south side of the lava dome suggests that the total volume change represented by the deformation between late September and October 6 is about 16 million cubic meters (21 million cubic yards). The average rate of change is about 2 million cubic meters per day (2.6 million cubic yards per day). If this figure represents the rate of intrusion of magma into shallow levels of the dome and(or) underlying crater floor, it is an intrusion rate about twice that measured during dome-building eruptions at Mount St. Helens in the 1980s.

As a result of the intense unrest of the past 11 days, we infer that magma is at a very shallow level. During times of unrest, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of unrest over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of unrest to continue during coming days. Escalation in the degree of unrest and perhaps an eruption could occur suddenly or with very little warning. There may be little time to raise the alert level before a hazardous event occurs. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show winds early this evening will remain westerly becoming northwesterly later. Any ash clouds will drift eastward (tonight) and southeastward (early tomorrow morning).



 

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Standard USGS Update

Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. During such eruptions, episodic changes in the level of activity can occur over days to months. The eruption could also intensify suddenly or with little warning and produce explosions that cause hazardous conditions within several miles of the crater and farther downwind. Small lahars could suddenly descend the Toutle River if triggered by heavy rain or by interaction of hot rocks with snow and ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS) but could pose a hazard along the river channel upstream.

Potential ash hazards to aviation: Under current eruptive conditions, small, short-lived explosions may produce ash clouds that exceed 30,000 feet in altitude. Ash from such events can travel 100 miles or more downwind.

The U.S. Geological Survey and the University of Washington continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

My intent with this page is to provide a clearning house for links to the current activity at Mt.St.Helens. Please send me any links of interest that you may come across, whether for permanent sites or for news reports. I'm not going to be able to do this all alone and all help will be appreciated.

(Disclaimer— I have no association with anyone or any organization, and speak only for myself. Links and quotes are provided for information only.)

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