Volcanic mountains

USGS scientists say volcanic unrest in Cleveland continues

Cleveland Volcano continues to show signs of unrest. Image: Max Kaufman/Alaska Volcano Observatory/University of Alaska Fairbanks, Geophysical Institute

A large, potentially dangerous volcano is not erupting at this time, but USGS scientists say that may change at Cleveland volcano where they have the volcano’s alert level and aviation color code. on ADVISORY/YELLOW due to volcanic unrest there.

This large stratovolcano, located in the Island Group of Four Mountains in Alaska’s Aleutian Range, is 5,676 feet tall and almost perfectly symmetrical. One of the most active volcanoes in the Aleutian Arc, Cleveland has erupted at least 22 times in the past 230 years. More recently, Mount Cleveland erupted three times in 2009, twice in 2010, once in 2011, and in 2016 and 2017. A small eruption occurred on June 2, 2020.

The volcano is monitored by the Alaska Volcano Observatory (AVO), which is a joint program of the US Geological Survey (USGS), the University of Alaska Fairbanks Geophysical Institute (UAFGI), and of the Geological and Geophysical Division of the State of Alaska. Surveys (ADGGS). AVO is similar to the Hawaii Volcano Observatory (HVO) which monitors Hawaii’s three active volcanoes: Kilauea, Mauna Loa and Hualalai. In the case of AVO, they are monitoring Cleveland, Semisopochnoi, Pavlof and Great Sitkin, all of which are currently on watch or advisory. Alaska is home to many volcanoes, however; there are over 130 volcanoes and volcanic fields that have been active in the past 2 million geologically young years. 50 have been active since the mid-1700s and AVO is also studying them.

A series of fissures eject lava near the summit of Mauna Loa in 1984. Image: Griggs, JD/Public Domain/USGS
A series of fissures eject lava near the summit of Mauna Loa in 1984. Image: Griggs, JD/Public Domain/USGS

According to AVO, while some unrest continues in Cleveland. seismicity remains low and no explosive activity has been detected on local or regional networks. AVO adds that no unusual activity was seen in cloudy satellite views over the past day.

“Episodes of lava outpouring and explosions can occur without prior warning,” warns AVO. “Cleveland explosions are normally short-lived and only pose an aviation hazard in the immediate vicinity of the volcano. Larger explosions that pose a more widespread hazard to aviation are possible but are less likely and do occur. less frequently.

When operational, Cleveland Volcano is monitored by only two seismic stations, which limits AVO’s ability to accurately locate earthquakes and detect precursor unrest that could lead to an explosive eruption. Early detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.

Aviation codes are green, yellow, orange or red. When there is insufficient ground instrumentation to establish that a volcano is at a typical background level of activity, it is simply “unassigned”. While green signifies typical activity associated with a non-eruptive state, yellow signifies that a volcano is showing signs of elevated unrest above known background levels. When a volcano shows increased or increasing unrest with increased potential for eruption, it turns orange. Finally, when an eruption is imminent with a significant emission of volcanic ash expected into the atmosphere or an eruption is in progress with a significant emission of volcanic ash into the atmosphere, the code turns red.

The first image of the new <a class=volcanic eruption, taken by a Coastguard helicopter, shows lava flowing from a 200m fissure. Image: Icelandic Meteorological Office” width=”300″ height=”169″ srcset=”https://weatherboy.com/wp-content/uploads/2021/03/IcelandEruption-300×169.jpg 300w, https://weatherboy.com/wp-content/uploads/2021/03/IcelandEruption-1024×576.jpg 1024w, https://weatherboy.com/wp-content/uploads/2021/03/IcelandEruption-768×432.jpg 768w, https://weatherboy.com/wp-content/uploads/2021/03/IcelandEruption-1536×864.jpg 1536w, https://weatherboy.com/wp-content/uploads/2021/03/IcelandEruption.jpg 2016w” sizes=”(max-width: 300px) 100vw, 300px”/>
The first image of the new volcanic eruption, taken by a Coastguard helicopter, shows lava flowing from a 200m fissure. Image: Icelandic Meteorological Office

Volcanic activity alert levels are normal, advisory, watch or warning. As with aviation codes, if the data is insufficient, it is simply labeled as “unassigned”. When the volcano is at typical background activity in a non-eruptive state, it is considered normal. If the volcano shows signs of elevated unrest above background, an advisory like the one currently in effect for Cleveland is issued. If a volcano exhibits increased or increasing unrest, a watch is issued while a warning is issued when a dangerous eruption is imminent.

Cleveland explosions typically produce relatively small volcanic ash clouds that dissipate within hours; however, larger ash emissions are possible, especially if the stratovolcano experiences a full eruption. Stratovolcanoes have relatively steep sides and are more cone-shaped than shield volcanoes. Unlike flatter shield volcanoes found in Hawaii, in a stratovolcano like Cleveland, lava accumulates around the vent forming a steep-sided volcano. Stratovolcanoes are more likely to produce explosive eruptions due to the buildup of gas in the viscous magma inside