Mount St. Helens rumort

[Angie]

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Mount St. Helens update
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Larger Steam and Ash Release at Mount St. Helens

A steam release began at 9:03 am PDT today, October 5, 2003, generating a
steam and ash plume that completely filled the crater and rose above the
summit (to about 12,000 to 13,000 feet altitude) and was carried to the NNE
by the prevailing wind. Steam and ash release continued for roughly an
hour. More ash was released than on October 4, and an ashfall advisory was
in effect until 2 pm PDT for the southern Washington Cascades, but then was
cancelled around noon as the plume dispersed. Light ashfall was reported in
several small communities downwind. Seismicity decreased significanly
during and after the event but did not cease.

After the air in the crater cleared, it was possible to see the Oct. 1 vent
in the glacial ice adjacent to the southern edge of the dome. The vent has
widened and is filled with a meltwater pond about 120 feet across filled
with floating ice blocks and possibly bubbling with gas. The water itself
is not boiling.

Uplift has continued at the interface of the glacier and dome immediately
East of the Oct. 1 vent. Estimates by the USGS are that this portion of the
dome has been uplifted about 150 feet since the beginning of the current
unrest. A new, vigorous fumarole has developed in a small vent on the dome
just North of the Oct. 1 vent.

Todays ash will be sampled and analyzed for a juvenile magmatic component.


Viele Grüße,
Angie

[Angie]

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Mount St. Helens updates
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U.S. Geological Survey, Vancouver, Washington
University of Washington, Pacific Northwest Seismograph Network, Seattle,
Washington
Mount St. Helens Alert Level Change

Past Alert Level: Volcano Alert (Alert Level 3); aviation color code RED
New Alert Level: Volcano Advisory (Alert Level 2); aviation color code ORANGE

October 6, 2004 9:15 A.M., PDT

Following yesterday morning's steam-and-ash eruption, seismicity dropped to a
low level and has remained low. Low-level tremor observed following the
eruption is also gradually declining. Lack of earthquake and rockfall signals
suggest that deformation of the uplift area on the south side of the 1980-86
lava dome has slowed. Brief visual observations this morning from Coldwater
Visitor Center showed weak steam emissions from the crater. We infer that the
vigorous unrest of the past few days has lessened and that the probability of
an imminent eruption that would endanger life and property is significantly
less than at any time since Saturday, October 2, when the alert level was
raised to Volcano Alert (Level 3). Therefore, we are lowering the alert level
to Volcano Advisory (Alert Level 2).

Such decreases in the level of unrest, which may reflect a decrease in the rate
of magma movement, have been common at Mount St. Helens during eruptions in
1980-86 and also at similar volcanoes elsewhere. Episodic changes in level of
unrest over periods of days to weeks, or even months, are possible. We don't
think that the current episode of unrest is over and we expect fluctuations in
the level of unrest to continue during coming days and months. Everyone should
be aware that escalation in 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.

------
Mount St. Helens Update, October 6, 2004, 7:00 a.m, PDT

Current status is Volcano Alert (Alert Level 3); aviation color code RED

Seismicity overnight has remained at very low levels. After the vigourous steam-
and-ash emission of yesterday morning, seismicity dropped with individual
events becoming smaller. By about 5 p.m. PDT yesterday, individual events
became rare and as of 11:00 p.m., seismicity has been stable at a low level.

Yesterday, field crews continued to harden GPS sites for the approaching winter
and retrieved data. The GPS sites on the dome survived the steam-and-ash
emission and data are being received and processed at the observatory. The
station on the northern flank of the dome, shows a trend of northward
displacement totaling 2 cm in the last three days. This is the same sense of
movement recorded by the nearby station that was destroyed by the first steam-
and-ash emission on 1 October. Data from the other two stations on the dome,
which were installed on 4 October are currently being analyzed. Data from GPS
instruments on the outer flanks of the volcano show no movement of the outer
flanks.

No gas measurements were made yesterday. A seismic crew installed an additional
broadband seismometer on the northwest flank of the volcano which will help
show a broader range of seismic energy release. With the help of the U.S.
Forest Service, field crews installed an antenna mast for a VSAT uplink which
will improve our ability to retrieve data from the field.

It began raining t the mountain at about 7:30 p.m. PDT. By about 9:30 p.m.
about 0.1 inch of rain had fallen. Overnight, the acoustic flow monitoror (AFM)
in the crater indicated that several small debris flows had moved past the
site. By midnight, higher flows were recorded at a station on the pumice plain,
but none were large enough to trigger an automatic alert. We expect these types
of flowage events to recur during intense rainstorms.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA),
combined with eruption models, show winds this morning are from the west-
southwest such that any ash clouds will drift to the east-northeast.

We continue to monitor the situation closely and will issue additional updates
and Alert Level changes as warranted.

Press conferences will continue to be held at the Headquarters office of the
Gifford Pinchot National Forest. The morning press conference is at 9:30 AM. If
activity remains low, we will do a show-and-tell of some of the instruments
were are using to monitor the volcano at the press conference.


Viele Grüße,
Angie

[Angie]

10. Oktober 2004
 
Neuer Dampf vom Mount St. Helens

10. Oktober 2004 Der Vulkan Mount St. Helens hat am Sonntag eine neue Dampfwolke aus seinem Krater geschleudert. Dunkler Rauch stieg gut 100 Meter über dem Berg im amerikanischen Staat Washington auf. Ob darin auch Asche enthalten war, konnten die Geologen vor Ort zunächst nicht feststellen.

Sie registrierten aber seit Samstag zunehmende Erderschütterungen im Bereich des rund 2.550 Meter hohen Vulkans. Alle ein bis zwei Minuten komme es zu Erdstößen bis zur Stärke von 2,4 auf der Momentmagnitude, erklärten die Wissenschaftler, die seit dem 23. September schon Tausende kleine Erdbeben gemessen haben. Ihrer Ansicht nach gibt es aber keine Anzeichen, daß eine größere Eruption unmittelbar bevorsteht.

Die Alarmstufe wurde deshalb auch nicht angehoben, doch wurden seit Anfang Oktober schon Tausende Anrainer evakuiert. Auf der Südseite des Vulkans wurde eine Lavablase beobachtet, die inzwischen auf mindestens 100 Meter anwuchs.

Die jüngsten Aktivitäten des Mount St. Helens waren die stärksten seit 18 Jahren. Ein etwaiger Ausbruch würde nach den Vermutungen der Wissenschaftler allerdings weit schwächer ausfallen als der vom 18. Mai 1980. Damals wurden 57 Menschen getötet, und die Wucht der Eruption riß etwa 390 Meter von der Vulkanspitze weg.

Text: FAZ.NET mit Material von AP
Bildmaterial: AP, Reuters


Neuigkeiten per Mail von Lisa Koenig habe ich leider dzt. nicht.


Viele Grüße,
Angie

[Angie]

Mt. St. Helens update 13. 10., 23:53:

Following a steam-and-ash emission at St. Helens on 5 October, seismicity dropped to low levels and CVO reduced the warning from Volcano Alert (Alert Level 3: aviation color code Red), to Volcano Advisory (Alert Level 2: aviation color code Orange). During 6-12 October, seismicity was at low-to-moderate levels, with the highest magnitude earthquakes (M 2.4) occurring at a rate of one every 2 minutes on 8 October.

On 6 October only weak steam puffs were emitted from the volcano and CVO scientists confirmed that the top of the area of intense uplift was at or slightly above the highest point on the lava dome, which suggested that some uplift occurred during the period of low seismicity. Scientists also confirmed that small lahars spilled out of the crater and onto the Pumice Plain during a rainstorm the evening of 5 October. Lahars traveled a short distance toward Spirit Lake and the North Fork Toutle River. CVO received reports that a light dusting of ash from the emission on 5 October affected the eastern part of Mount Rainier National Park, ~110 km NNE of St. Helens. A new steam vent opened during the evening of 6 October, joining two that had been present for several days.

Measurements from recent photographs and LIDAR (LIght Detection And Ranging) showed that as of 7 October the intensely deformed and uplifted area on the S side of the 1980-86 lava dome was ~400 m (N-S) by ~490 m (E-W) with a maximum uplift of about 90-120 m. Additional analysis revealed that the total volume change represented by the deformation between late September and 6 October was ~16 million cubic meters. The average rate of change was ~2 million cubic meters per day. On 11 October, 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. A gas-sensing flight on 11 October measured fluxes of sulfur dioxide and carbon dioxide that were similar to, or slightly smaller than, those measured on 7 October.

CVO reported on 13 October, "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."

Background. Prior to 1980, Mount St. Helens formed a conical, youthful volcano sometimes known as the Fuji-san of America.  During the 1980 eruption the upper 1,400 m of the summit was removed by slope failure, leaving a 2 x 3.5 km horseshoe-shaped crater now partially filled by a lava dome.  Mount St. Helens was formed during nine eruptive periods beginning about 40-50,000 years ago, and has been the most active volcano in the Cascade Range during the Holocene.
The modern edifice was constructed during the last 2,200 years, when the volcano produced basaltic as well as andesitic and dacitic products from summit and flank vents.  Historical eruptions in the 19th century originated from the Goat Rocks area on the N flank, and were witnessed by early settlers.


Viele Grüße,
Angie

[Angie]

Update vom 22. 10. 04, 9:54:

During 13-18 October, seismicity was at low levels at St. Helens and growth of the new lava dome inside the volcano's crater continued. Gas-sensing flights on 13 October detected low levels of sulfur dioxide and hydrogen sulfide, but no carbon dioxide. Measurements of flow rate and temperatures in streams draining the crater showed no significant change from late September values. On 14 October, visual observations and thermal imaging of the crater showed enlargement of both the section of intense deformation and uplift on the S side of the 1980-86 lava dome, and the new lobe of lava in the W part of that area.
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. On the 14th only sulfur-dioxide flux was detected, and there was no detectable carbon dioxide or hydrogen sulfide.
Thermal imaging showed slow extrusion of lava continuing on the 14th. Global Positioning System (GPS) measurements on 15 October continued to indicate only minor deformation of the northern part of the 1980-86 dome and no deformation of the volcano's outer flanks. Parts of the area of uplift and new lava dome were higher than when previously seen on 14 October. On the evening of 16 October, rainfall triggered a small debris flow that traveled N from the crater and changed rapidly into a muddy stream flow within 5 km of the volcano.
Through 18 October, the level and character of seismicity was consistent with a continuing rise of magma driving uplift of the crater floor and feeding the surface extrusion of lava. According to CVO, low rates of seismicity and gas emission suggested that the lava reaching the surface was gas poor.

CVO stated on 18 October that 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 kilometers 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.


Viele Grüße,
Angie

[Angie]

Update 27. 10. 04, 20:30 pm bei mir eingelangt:

MOUNT ST. HELENS VOLCANO
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.

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.

For additional information, background, images, and other graphics:
http://vulcan.wr.usgs.gov/News/framework.html


Viele Grüße,
Angie

[Angie]

Hi an alle Interessierten,

soeben bekam ich einen Bericht vom Mt. St. Helens Ausbruch 1980. Ich weiß nicht, ob das jemanden interessiert, ich stelle es einfach mal in diesen Thread.


„Vancouver, Vancouver, this is it!“

Am 18. Mai 1980 explodierte der Mount St. Helens. Rückblick auf ein Ereignis, das sich jederzeit wiederholen kann.

Sonntag, 18. Mai 1980. Noch vor Sonnenaufgang beginnt die tägliche Routine. Ein Flugzeug der „Oregon National Guard“ überfliegt den Vulkan und macht Infrarotaufnahmen. Die Entwicklung der Filme und die Auswertung der relativen Temperaturverteilung der Oberfläche wird noch einige Stunden dauern; die Ergebnisse aber werden nicht mehr relevant sein. Die Seismizität in den frühen Morgenstunden ist moderat, ohne besonderen Befund.

Am ständig besetzten Beobachtungsstützpunkt „Coldwater II“, 9,2 Kilometer nordnordwestlich des Gipfels und innerhalb der Sperrzone, unternimmt der Geologe David Johnston seine morgendlichen Laser-Distanzmessungen von der sich in den letzten Wochen ständig weiter aufblähenden Nordflanke und sendet diese gegen 7 Uhr nach Vancouver: keine signifikanten Veränderungen.

Der Himmel über der Region ist wolkenlos. Hobby-Angler, einige Waldarbeiter und andere Frühaufsteher erfreuen sich der klaren Luft und einer warmen Brise aus Westen. Manche der Amateurbeobachter und -funker sind bereits auf ihren Posten, ausserhalb der roten Sperrzone. Unter ihnen Gerald Martin, einen Höhenzug weiter weg als Johnston, Position 11,5 km N, der Photograph Reid Blackburn vom „Vancouver Columbian“, der einen Auftrag für das Magazin „National Geographic“ in der Tasche hat, Position 13,7 km NW, Robert Rogers und die Kearneys, allesamt Amateurfunker, Position 12,2 km W sowie Gary Rosenquist, Amateurfotograph, und in seiner Nähe Keith Ronnholm, Geophysiker, Position 17,6 km NE.

Die Geologen Keith und Dorothy Stoffel, die gerade in der Gegend von Spokane arbeiten und an einer Konferenz in Yakima teilnehmen, entscheiden sich kurzfristig, nachdem ihnen eine Überflugerlaubnis erteilt wurde, den Vulkan aus der Luft zu beobachten. Um 7 Uhr 15 chartern sie in Yakima ein Flugzeug.

Etwa um 7 Uhr 50 dringen sie in den gesperrten Luftraum ein. Mehrmals umkreisen sie im Uhrzeigersinn die Gipfelregion und machen Beobachtungen und Photos. Beim vierten und letzten Überflug gegen halb neun sehen sie zunächst, wie Fels- und Eisblöcke des Gipfels vom Rand in den Innenkrater stürzen. Sekunden später beobachten sie, wie die gesamte Nordflanke des Berges in Bewegung gerät, durchgeschüttelt wird, sich kräuselt und dann in nördlicher Richtung auf den Spirit Lake zu hinab gleitet. Sie hatten die Initialsekunden eines gigantischen Bergsturzes miterlebt. Jetzt folgen die ersten Eruptionswolken, zunächst am unteren Ende der nun exponierten Erdrutsch-Gleitfläche, dann weiter oben, unterhalb des Gipfels; sie wachsen extrem schnell zu unglaublichen Dimensionen heran.

Um 8 Uhr 32 hat ein Erdbeben der Stärke 5,2 den Bergsturz ausgelöst. Etwa 20 bis 30 Sekunden später folgt die heftige, lateral nordwärts gerichtete Explosion. Am Boden ist Johnston mit der Erste, der den Bergrutsch wahrnimmt. Er schreit in sein Funkgerät: „Vancouver, Vancouver, this is it!” Ein weiterer Satz ist zu verstümmelt, als dass er verstanden werden könnte. Wegen atmosphärischer Störungen erreicht die Warnung nicht das Zentrum in Vancouver, andere Amateurfunker nehmen seine Nachricht auf.


Ein Naturlabor

Die katastrophischen Ereignisse und Prozesse rund um den Vulkanausbruch, hinterfragen unsere Denkweise über das Erdgeschehen. Verändert sich die Erde durch langsame und graduelle Prozesse, die durch Akkumulation im Verlauf langer Zeiträume kleine Änderungen bewirken? Oder haben rasche Prozesse innerhalb kürzester Zeit deutliche geologische Veränderungen hervorgerufen?

Die Geologie ist eine historische und keine exakte (Natur-)Wissenschaft. Die in der Vergangenheit abgelaufenen, grossräumigen oder gar globalen Prozesse der Veränderung der Erdkruste wiederholen sich in den wenigsten Fällen. Sie sind nicht reproduzierbar wie wir es beispielsweise aus der Physik kennen. Auch gibt es kein Testlabor der Grösse Erde. Aber geologische Ereignisse wie der Ausbruch des Mount St. Helens haben die Funktion und Grösse eines Miniatur-Labors.

So gesehen ist der Mount St. Helens ein Anschauungsobjekt aller erster Güte; doch nicht wegen seiner Eruption alleine, sondern wegen einer ungewöhnlichen Konzentration vielfältigster und auch bis dahin nie in diesem Spektrum beobachteter rascher Erosions- und Sedimentationsprozesse und dem Wissen, wie diese abgelaufen sind.

Obwohl der Ausbruch erwartet worden war, haben viele Wissenschaftler und Behörden die Dynamik der Eruption und seine Folgen unterschätzt. 57 Menschen kamen ums Leben. Auch daraus lässt sich ableiten, dass die geologischen Erkenntnisse über katastrophische Vorgänge noch unzureichend sind und deren Auftreten in der Erdgeschichte noch nicht ausreichend erforscht ist.

Es glich einer Kettenreaktion: Eingeleitet wurde die Explosion des Mount St. Helens durch ein Erdbeben und einen Erdrutsch, bei dem rund zwei Kubikkilometer Material bewegt wurden. Das Abgleiten des Gipfels und des Nordhangs senkte den Druck innerhalb des Vulkans, wobei sich überkritisches Wasser schlagartig in Dampf umwandelte. Die nordwärts gerichtete Dampfexplosion setzte ein Energieäquivalent von 20 Millionen Tonnen TNT frei; dabei wurde eine Waldfläche von fast 400 km2 umgeknickt.

Die pilzförmig heranwachsende Eruptionssäule stieg bis in 20 Kilometer Höhe auf. Die Magmenkammer im gipfelnahen Reservoir wurde durch die pausenlos explodierenden und hochschiessenden Gas- und Aschesäulen nach und nach entleert.

Die nach Osten über mehrere Bundesstaaten driftenden Aschewolken verfinsterten im Laufe des Tages ganze Regionen. Rund 150 Kilometer vom Mt. St. Helens entfernt verfinsterte sich in der Stadt Yakima (Bundesstaat Washington) am 18. Mai um die Mittagszeit der Himmel. Die Strassenbeleuchtung schaltete sich automatisch an. Die erste Lage des Aschenregens bestand aus “Salz und Pfeffer”. Das waren sandkorngrosse Teilchen von dunklem Gestein und helleren Feldspatfragmenten, über die sich eine dickere Schicht aus staubkorngrossen Glasteilchen legte.

30 Kilometer nördlich von Yakima lagerte sich die Asche mit ca. 20 mm Mächtigkeit ab. In der 330 Kilometer entfernten Stadt Ridswill erreichte die Aschenlage über 70 mm. Selbst in der 430 Kilometer vom Vulkan entfernten Stadt Spokane, wo lediglich 5 mm Asche fielen, wurde es um 15 Uhr finster, so dass die Sichtweite auf 3 Meter sank. Schlammströme verwüsteten über Dutzende von Kilometern - auch weit abseits der Explosionszone - Flüsse und Täler.

Gegen Abend klang die Eruptionstätigkeit ab. Während des neunstündigen Ausbruchs hatte der Vulkan eine Energie freigesetzt, die 400 bis 430 Millionen Tonnen TNT entsprach. Das ist vergleichbar mit der Gewalt von 20.000 Hiroschima-Atombomben. Die gesamte Nordflanke des Mount St. Helens war weggesprengt. Der Vulkan hat 400 Höhenmeter eingebüsst (von 2950 m auf 2550 m); ein Areal von 600 km2 war vollkommen verwüstet.


Viele Grüße,
Angie

[Mel on Tour]

Mich interessiert das    Ich verfolge auch Deine Updates immer mit. Momentan scheint sich am Vulkan nicht viel zu tun.

[Anne]

Hi Angie,
ich schau auch immer rein- danke für Deine Informationen.
Wir waren schon einige Male dort und vielleicht nächsten Sommer wieder- mal sehen, was bis dahin so passiert.
Tschüß
Karin

[Angie]

Hallo Mel und Karin,

dann war meine "Mühe" doch nicht ganz umsonst


Viele Grüße,
Angie

[Eisi]

Hi Angie
Nein, Deine Mühe war garantiert nicht umsonst. Auch ich verfolge das Geschehen am St.Helens. War selbst schon mehrmals da. Vulkane sind halt einfach etwas schönes.

Gruss Eisi

[Angie]

Hi Eisi,

Vulkane sind halt einfach etwas schönes.

Du sprichst mir aus der Seele
Ich habe mir gerade zum x-ten Mal unseren diesjährigen Heli-Flug über den aktiven Pu'u O'o angesehen  Muss jetzt direkt überlegen........ Wenn wir heute schon nach Frankfurt fliegen, warum dann nicht gleich weiter nach Hawaii    

Viele Grüße,
Angie

[Anne]

Hi Angie,
wir wollen wahrscheinlich 2006 nach Hawaii- wegen der Vulkane.
Ich werde Dein Wissen bis dahin noch anzapfen müssen.....

Aber den Mt St Helens finden wir auch sehr aufregend und haben in den letzten Jahren von beiden Seiten das Neuwachstum der Vegetation und des Hügels im Krater verfolgt. Den Film kennen wir natürlich auch.
Bitte schreib weiter, was Du herausfindest.
Tschüß
Karin

[Angie]

@Anne

wir wollen wahrscheinlich 2006 nach Hawaii- wegen der Vulkane.  
Ich werde Dein Wissen bis dahin noch anzapfen müssen.....

Du kannst mein Wissen über Hawaii gerne anzapfen  Dann werden wir sehen, ob ich die  Prüfung bestehe oder nicht


Viele Grüße,
Angie

[Angie]

So, weiter geht's mit dem Mt. St. Helens:

05 Nov 04 MSH Update

U.S. Geological Survey, Vancouver, Washington University of Washington, MOUNT ST. HELENS VOLCANO
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 westward to southwestward.

Visibility is excellent and likely will remain so throughout the day.  A steam plume is rising passively and drifting south and southwestward over the crater rim.  The plume occasionally contains minor ash, which falls out in the crater and on the southern flank of the volcano, darkening the new snow.

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 were in the field yesterday, the first opportunity following a spate of inclement weather.  Their findings:
 Sulfur dioxide (SO2) emission rates continue to be low and consistent with previous measurements.  No hydrogen sulfide (H2S) was detected.  Ash in the steam plume prevented an accurate measurement of carbon dioxide (CO2).

The elongated new dome, which extends southward from the 1980-1986 dome, has undergone substantial vertical growth since October 27.  A new mass of dacite has extruded upward by as much as 100 m.  Exposed rock faces have temperatures in the range 400-500 degrees Celsius, creating the incandescence that may be seen from the north on clear nights.  Field crews conducted geologic observation flights in the crater.  To collect samples they landed a helicopter on the new dome for the second time in two weeks.
The new dacite lava contains visible crystals of plagioclase, hornblende and hypersthene.  These samples are similar to those collected on October 27 and also to lava erupted at Mount St. Helens in the 1980s.

The steep new faces on the dome are generating small hot rockfalls and avalanches within the crater.  The finer particulate from these deposits roils upward within the steam plume, rising to about 11,000 ft altitude, or about 2,600 ft above the crater rim.  Consequently the south and southwest flank of the volcano have received a notable dusting of ash.  This localized ash poses no threat beyond the near slopes of the volcano.

Most dome growth has been vertical, with only about 30 m of outward growth in some directions.  The thick glacial ice that forms a buttress on the south and east sides of the dome remains largely intact.  All dome growth is contained within the Mount St. Helens crater.

A continuous GPS station north of the volcano at Johnston Ridge Observatory has moved to the south by about 2 cm since late September or early October.
This slow shift may reflect a depletion of magma in the subsurface at 5-10 km depth.  To confirm this result, five new GPS receivers were positioned around the volcano's flanks 5-10 km from the crater to better track  hanges in the deeper parts of the magmatic system.  Two additional units will be deployed today.


Viele Grüße,
Angie