Monthly Archives: March 2009

Why are there so many volcanoes in the Pacific Northwest and Alaska?

  The distribution of volcanoes in the northwest and Alaska is the result of plate tectonics. In the northwest, the oceanic Farallon Plate is being pushed beneath (subducted) the continental margin of the North American Plate. When the subducted plate … Continue reading

Posted in FAQ

Redoubt, Alaska, USA

On 18 March, AVO lowered the Alert Level for Redoubt to Advisory and Aviation Color Code to Yellow because seismicity declined to levels recorded prior to the ash emission on 15 March. Seismicity remained low the next day. Shallow earthquake … Continue reading

Posted in Volcano Activity Reports | Tagged

Koryaksky, Kamchatka Peninsula, Russia

KVERT reported that seismic activity at Koryaksky was elevated on 13 March and at background levels on the other days during 14-20 March. Observers reported that gas plumes containing a small amount of ash rose to an altitude of 4 … Continue reading

Posted in Volcano Activity Reports | Tagged

Hunga Ha’apai, Tonga

Based on information from Tonga Meteorological Services, analysis of satellite imagery, and pilot observations, the Wellington VAAC reported that during 18-19 March ash plumes from Hunga Tonga-Hunga Ha’apai rose to altitudes of 4-5.2 km (13,000-17,000 ft) a.s.l. and drifted NE … Continue reading

Posted in Volcano Activity Reports | Tagged

Galeras, Colombia

On 24 March, INGEOMINAS lowered the Alert Level for Galeras to III (Yellow; “changes in the behavior of volcanic activity”). During the previous week daily sulfur dioxide levels were high. Earthquake levels were low in both intensity and occurrence. During … Continue reading

Posted in Volcano Activity Reports | Tagged

Amazing Tongan Eruption Photos

Alan Taylor from the Big Picture Blog on Boston.com has posted some amazing images of the Tongan eruption. I’d link there directly except the public comments are just not exactly… well… scientific. Here are a few low rez linked out … Continue reading

Posted in News

How do volcanoes affect the atmosphere and climate?

This photo shows the large white billowing eruption plume from Rabaul being carried in a westerly direction by the weak prevailing winds. At the base of the eruption column is a layer of yellow-brown ash being distributed by lower level … Continue reading

Posted in FAQ