Due to the possibility of volcanic unrest, the United States Geological Survey (USGS) and their Alaska Volcano Observatory (AVO) have raised the advisory level and color code to the YELLOW / ADVISORY at the Davidof Volcano in Alaska.
Home to many tufted puffins and horned puffins, Davidof Island is believed to be part of a circular complex of island remnants of an ancient twin-coned volcano that was destroyed in a catastrophic eruption during the late Tertiary period. The Tertiary Period began about 66 million years ago with a mass extinction event that killed-off the dinosaurs and ended when the ice ages of the Quaternary Period began, about 2.6 million years ago. Nicknamed the “Aleutian Krakatoa”, the volcano on Davidof Island is located in the west-central Aleutians.
According to AVO, over the last three days, a swarm of earthquakes struck around the Davidof volcano. The largest earthquake to date happened this morning at about 10:45 am local time and had a magnitude of 4.2. “This swarm may be associated with volcanic unrest or it could also be due to regional tectonic activity,” AVO said in a statement.
The Davidof Volcano located along the “Ring of Fire”, which is a region around the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur. Caused by plate tectonics, lithospheric plates under and around the Pacific Ocean move, collide, and/or are destroyed, creating the seismic activity the Ring of Fire is famous for.
Volcanoes in this portion of the Ring of Fire are monitored by the Alaska Volcano Observatory (AVO), which is a joint program of the U.S. Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). The 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 monitor Cleveland, Semisopochnoi, and Veniaminof too.
Alaska is home to many volcanoes, though; there are more than 130 volcanoes and volcanic fields which have been active within the geologically young last 2 million years. 50 have been active since the mid 1700s and AVO studies those too.
AVO is responsible for issuing Aviation Codes and Volcanic Activity Alert Levels. Aviation Codes are green, yellow, orange, or red. When ground-based instrumentation is insufficient to establish that a volcano is at a typical background level of activity, it is simply “unassigned.” While green means typical activity associated with a non-eruptive state, yellow means a volcano is exhibiting signs of elevated unrest above known background levels. When a volcano exhibits heightened or escalating unrest with the increased potential of eruption, it jumps to orange. Finally, when an eruption is imminent with significant emission of volcanic ash expected in the atmosphere or an eruption is underway with significant emission of volcanic ash into the atmosphere, the code becomes red. Volcanic Activity Alert levels are normal, advisory, watch, or warning. As with aviation codes, if 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 exhibits signs of elevated unrest above background level, an advisory is issued. If a volcano exhibits heightened or escalating unrest, a watch is issued while a warning is issued when a hazardous eruption is imminent.