Source: Smithsonian Institute's Global Volcanism Program, Alaska Volcano Observatory

On February 8th, Cleveland Volcano, one of the many volcanoes that makes up Alakan's Aleutian Island Chain, erupted an ash cloud. Satellite observations of this ash cloud first put the cloud at an estimated 1.5 km (5,000 feet) above sea level. At this point, the ash cloud was observed drifting 12 km SE of the volcano. Later in the day, Alaska Volcano Observatory received a pilot report that the cloud was visible at 20,000 feet. Volcanic clouds at this altitude are extremely hazardous to aircraft. Subsequent satellite imagery showed the cloud drifting NW at a height of 16,000 feet. The eruption was relatively small and it was lucky that the cloud was observed as the volcano had been covered with clouds for most of the preceeding week.

The eruption probably started small with a lower ash cloud which drifted to the SE in the lower atmosphere. As the eruption continued and grew with energey, a larger, higher ash cloud was produced that went higher in the atmosphere where the wind was traveling in the opposite direction to the NW. This process is called cloud shearing. In satellite imagery, it would look like two thin streams of ash traveling in opposite directions from the volcano, producing a sort of anvil shaped image. This is not an uncommon process for volcanic clouds originating from Cleveland Volcano.

As of 02/18/08, AVO has posted the following status report:

Clouds obscured satellite views of Cleveland. No reports of activity have been received. AVO monitors Cleveland Volcano with satellite imagery as weather allows. The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions of ash that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.Please see http://www.avo.alaska.edu/activity/Cleveland.php for more information.

On January 1, 2008 at approximately 2120 GMT, Lliama Volcano in Chile erupted an ash and gas cloud high into the atmosphere. Unconfirmed reports from the Buenos Aires Volcano Ash Advisory Center put the ash cloud at an altitude of about 12.5 km.

Lliama is one of Chile's largest and most active volcanoes, with historical activity being recorded as far back as the 17th century. Lliama is a stratovolcano, meaning that it has high, steeply-sloped flanks that have formed from thousands of years of ash eruptions and lava flows.

The eruption produced a moderate SO2 cloud that stayed in the atmosphere for several days; traveling east over South America and then over the Atlantic Ocean towards the island Tristan de Cunha. There was some initial concern that the gas plume could mix with atmospheric water and produce a sulfuric haze that could block sunlight and potentially cause some global cooling, as the 1991 Mt. Pinatubo eruption cloud did. In this case, however, satellite data have confirmed that the amount of SO2 in the Llaima cloud was three orders of magnitude less than the SO2 in the Pinatubo cloud. So, this eruption is not expected to have an effect on the climate.

The big news this week out of the Smithsonian's Global Volcanism Program is that Krakatau Volcano is currently at an Alert Level 3 (on a scale from 1-4). Krakatau Volcano is located in the Indian Ocean right in between the islands of Sumatra and Java.

Many of you might have heard of Krakatau Volcano and its most infamous eruption in 1883 which all but wiped out the island of Krakatau and killed about 36,000 people. The actual eruption itself killed only about 4,500 people with ash falls (known to cause the collapse of rudimentary shelters) and pyroclastic flows (boiling hot gas and ash traveling at hurricane-wind speeds). The rest were killed by large tsunamis created by the eruption that swept away whole villages located on the surrounding low-lying coasts. Many books have been written about this eruption and the resulting devastation.

The eruptions from the 1883 event were so large that the ash cloud reached up to 20 km in the atmosphere and is said to have circled the globe twice. Additionally, the 1883 eruption of Krakatau is famous for its far reaching explosive noises. People as far as 2,000 km (1,242 miles) away were reported to have heard what they thought was distant gunfire, which was later established to be the volcano erupting.

Currently, the volcano is producing much smaller eruptions. It is erupting some smaller incandescent ejections which are reported to be rising 500-700 meters above the crater. Some ash clouds have also been observed above the crater, but they are probably too small to be observed by satellite imagery.

The volcano is no doubt being monitored very closely by Indonesia's Center of Volcanology and Geological Hazard Mitigation. No one wants a repeat of the 1883 devastation.

Hello! My name is Alexandra and I'm a PhD student at Michigan Technological University located in the beautiful Upper Peninsula of Michigan. My research is in volcanology and the monitoring of volcanic eruption ash clouds in the upper atmosphere (>10 km) using satellite data. These ash clouds are extremely hazardous to aircraft and can stay in the atmosphere for many days and travel many hundreds of kilometers from their source volcano. So far, there have been no ash cloud-aircraft encounters that have led to a crash. But in one of the most famous cases of an encounter - a KLM Royal Dutch Arilines 747 encountered an ash cloud from Redoubt Volcano, Alaska at 25,000 feet in 1989 - the aircraft lost power to all four engines and the pilots weren't able to restart the engines until they had "glided" out of the ash cloud. The plane was reported to have passed through the 13,000 foot mark before all four engines were restarted. That's a harrowing 12,000 foot descent with no power!!!

The purpose of this blog is to gain experience in earth science journalism, my true passion. I love writing and I love earth science (hence, the PhD in Geology) so I figured I would love combining the two and at the same time exposing the public to some of the great ongoing research in the natural hazard field that sometimes just stays in the realm of academia and never gets public exposure.

I have completed a minor in journalism and when I finished I went to the editor of our local newspaper, the Daily Mining Gazette, and asked if I could contribute a monthly column on current natural hazard events/research. He politely told me that no one around here would care about that stuff, but he did invite me to contribute a monthly column about being a college student. I figure some experience in public writing is better than nothing, so I am currently writing a monthly column called "Campus Life". However, I still want to try my hand at writing about earth sciences for the public, so that's why I started this blog.