Mount St. Helens: “The Ides of March?”

VolcanoWatch Weekly [17 Feb 2011]

Shinmoedake Update:

Some 2,500 people living near Shinmoedake volcano on Japan’s Kyushu island were advised earlier today to evacuate their homes after heavy rain threatened lahar avalanches, reports say.

VoW: Mount St. Helens

Mount St. Helens and Spirit Lake, as seen from Bear Cove. Image Source: U.S. Forest Service via USGS/CVO.

Phreatic eruption of Mount St. Helens, March 28, 1980, as seen from the north. Image by C.Dan Miller, USGS/CVO

Mount St. Helens, Washington  Ash Plume Path May 18, 1980

Click image to enlarge.

Mount St. Helens Volcano
Position: 46°12′ N 122°10’48” W,
Summit Elevation: 2,549 m (8,363 ft )
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN
Source: USGS/CVO

Recent observations:

An M4.3 earthquake struck the Mount St. Helens region this morning, 14 February 2011, at 10:35 a.m. PST (18:35 UTC) and was felt widely through southwestern Washington and Northwestern Oregon (http://earthquake.usgs.gov/earthquakes/dyfi/events/uw/02141835/us/index.html). Its exact magnitude may change by a few tenths from this value as records are further analyzed. The earthquake was followed by several aftershocks up to M2.8 over the next few hours (http://www.pnsn.org/recenteqs/latest.htm), the three largest of which were also reported felt. All of the earthquakes are located in an area about 8 kilometers (5 miles) north of the crater of Mount St. Helens, near the Johnston Ridge Observatory, at a depth of about 4 to 6 kilometers (2.5 to 4 miles).

Today’s earthquakes are in the same place as a small swarm that took place about two weeks earlier, on 29 January. These earthquakes are reminiscent of a swarm that took place about 30 years ago, when a swarm of small earthquakes began in August 1980, a few miles northwest of today’s activity. The 1980-1981 sequence climaxed with an M5.5 earthquake on 14 February 1981. Analysis of the 1981 events suggested that they occurred along existing faults in the Mount St. Helens seismic zone, a northwest to southeast trending system of faults in which Mount St. Helens lies. The Mount St. Helens seismic zone exhibits strike-slip motion, with the southwestern rocks slipping horizontally northwest relative to the rocks northeast of the fault zone. The fault zone likely exerts control on the location of Mount St. Helens volcano. Studies following the 1980 eruption suggested that the magma removed during the May 1980 eruption and subsequent lava-dome building caused faults along the seismic zone to slip in response to the magma withdrawal. Similar interaction of volcanic activity and tectonic fault movement is possible in the case of today’s earthquakes, but at present there appears to be no signs of unrest in the volcanic system.  USGS/Cascades Volcano Observatory, Vancouver, Washington

• Mount St. Helens “Current Activity Updates” Archives
• Eruption Chronology
• Mount St. Helens, Washington: Before, During, and After May 18, 1980  (1980 – 2004)

Summary of Weekly Volcanic Activity Report – 9 February to 15 February 2011

[Source: SI/USGS]

New Activity/Unrest:

• Fuego, Guatemala [Group F]
• Santa María, Guatemala  [Group F]
• Kirishima, Kyushu (Japan)  [Group J]

Map of Volcanoes

Map of Volcanoes. Background Map: University of Michigan. Designed and enhanced by Fire Earth Blog. Click image to enlarge.

Ongoing Activity:

• Dukono, Halmahera
• Karymsky, Eastern Kamchatka (Russia)
• Kilauea, Hawaii
• Kizimen, Eastern Kamchatka (Russia)
• Kliuchevskoi, Central Kamchatka (Russia)
• Poás, Costa Rica
• Sakura-jima, Kyushu
• Shiveluch, Central Kamchatka (Russia)
• Soufrière Hills, Montserrat
• St. Helens, Washington (USA)
• Suwanose-jima, Ryukyu Islands (Japan)
• Tengger Caldera, Eastern Java (Indonesia)

For additional information, see source.

Related Links:

• Messages From Earth’s Powerhouse
• A New Era of Intense Volcanic Unrest May Have Begun
• Earth’s Climate: A Solar Powered System
• World’s Dormant Volcanoes Firing
• Kamchatka Volcanoes The Fat Lady?

FEWW Volcanic Activity Forecast

• Sumatra’s Mt Kerinci Erupts
• Volcano Watch Weekly: 23 April 2009
• Weekly Volcano Watch: 16 April 2009
• Weekly Volcano Watch: 2 April 2009

• FEWW Volcano Links
• Volcanoes
• FEWW Earthquake Links

Other Related Links:

• U.S. Volcano Status Map
• Elevated Activity Page

Shinmoedake Saying Something?

Volcanic Ash Affecting Japan’s Air

Shinmoedake Volcano Continues to Erupt on Japan’s Kyushu Island

FIRE-EARTH is advised that volcanic ash from Shinmoedake has traveled to at least as far as the Osaka region, some 500km northeast of the volcano, affecting air “quality.”

A combination of volcanic ash and dust from China has created a haze in the atmosphere, reducing solar power generation in the region by up to 20 percent in the last 48 hours, local sources told the blog.

The 1,421-meter (4,660 feet) volcano in the Kirishima volcanic complex erupted today at about 9:40JST following three eruptions yesterday, ejecting a plume of ash and smoke up to 3,000m into the air, local reports say.

University of Tokyo’s Earthquake Research Institute professor Setsuya Nakada says a much larger eruption is possible.

“Following the first major eruption on Jan. 26, the second and the third eruptions occurred at one to three-day intervals. After the fourth eruption shortly before 8 a.m. on Feb. 1, however, a total of five eruptions, including the latest at around 8 a.m. on Feb. 3, occurred at shorter intervals of five to 15 hours.” Japan’s Mainichi Daily News said.

A lava dome created by the eruption covers the volcano’s crater, which is 700m wide and 200m deep.   The dome has reached a height of about 110m above the crater rim, a Geospatial Information Authority of Japan announcement on Feb. 2 said.

• Mt Kirishima Live
• Shinmoedake photos by Earthquake Research Institute, Univ.Tokyo

Sakurajima Volcano

Japan’s Meteorological Agency (JMA) has raised the alert level to 3 for Sakurajima volcano, located about 45 kilometers (28 miles) to the southwest. The volcano is one of Japan’s most active, accounting for more than 1,000 episodes  in 2010, the most activity recorded since 1982, JMA reported.

“Most worrying is the enormous damage that could be caused by volcanic rock spewed out of the mountain, as well as by pyroclastic flows. In fact, a volcanic rock about 50 centimeters in diameter was found about four kilometers from the crater, and in a forest about three kilometers from the crater, there is a hole 5 meters wide and more than 2 meters deep that was created when volcanic rocks struck the spot.” Said  a report.

Ash plume from Shinmoedake, Kirishima volcanic complex, Japan

A photo-like satellite image of Shinmoedake shows an ash plume from the volcano captured by MODIS on the Terra satellite on February 4, 2011. The volcanic ash has forced flight cancellations, stopped trains, made roads impassible and closed all nearby schoolsn. Source: NASA-EO. Click image to enlarge. Download larger image (511 KB, JPEG)

Shinmoe-dake Volcano continues to erupt violently. MODIS on Aqua satellite captured this photo-like image at 1:30 pm local time on February 3, 2011. “The image also shows a faint plume of ash and steam rising from Sakurajima, one of Japan’s most active volcanoes.” Source: NASA-EO. Click image to enlarge. Download larger image (926 KB, JPEG)

After a week of violent activity, the eruption of Japan’s Shinmoe-dake Volcano shows no signs of slowing down. This natural-color satellite image shows Shinmoe-dake on the morning of February 3, 2011. The image was acquired by the Advanced Land Imager (ALI) aboard Earth Observing-1 (EO-1) at about 10:30 a.m. local time, between an early-morning eruption at 3 a.m. and an early-afternoon eruption at 12:17 p.m. Image and caption: NASA-EO. Click image to enlarge. Download larger image (2 MB, JPEG)

Related Links:

• Japan’s Shinomoedake volcano erupts for a 2nd day
• FEWW Volcano Links
• Volcanoes
• FEWW Earthquake Links

Japan’s Shinmoedake volcano erupts for a 2nd day

Mt Shinmoedake continued to eject tephra Thursday

Shinmoedake volcano in southern Japan, which began erupting on Wednesday, ejecting rocks, ash and smoke about 4,600m  into the air, was still erupting on Thursday.

Local highways and railroads have become impassable as a result, and at least 4 flights to the area have been canceled as a precaution, reports say.

Shinmoedake volcano continued erupting for a second day on Thursday. Freeze frame from ITN news clip.

Shinmoedake Volcano Erupts

Natural-color satellite image of Shinmoedake volcano  captured by MODIS aboard NASA’s Terra satellite on January 26, 2011. Shinmoedake is a volcano in the Kirishima volcanic complex on Japan’s Kyushu island. Source: NASA-EO. Click image to enlarge.

Lightening is photographed using time exposure during an eruption from Mt Shinmoedake in the Kirishima volcanic complex on the border of Kagoshima and Miyazaki prefectures, southern Japan. Photo:  Shuji Uchimura/AP. Image may be subject to copyrights.

Video Clips

• ITN News Video
• ABC News Video

Related Links:

• FEWW Volcano Links
• Volcanoes
• FEWW Earthquake Links