Alaska Volcanoes: Great Sitkin, Cleveland, Prompt Alerts For High Background Activity

While many are watching the Kilauea volcano in Hawaii, two volcanoes in Alaska are threatening to steal some of the attention. Two volcanoes situated on islands off the coast of the state are showing warning signs of a possible eruption.

On the first day of July, the United States Geological Survey tweeted that the Great Sitkin volcano’s activity had increased above the usual background levels.

Officials are actually closely monitoring two Alaskan volcanoes, Mount Cleveland and Great Sitkin, a little closer than others. On June 26, there were small lava flows detected in the summit’s crater of the Cleveland volcano. A few days later on the 28th, the Alaska Volcano Observatory (AVO) put the volcano on watch and changed the aviation color code to orange.

The combination of the watch and the orange color code means the “volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain OR an eruption is underway that poses limited hazards including no or minor volcanic-ash emissions.”

On a neighboring island, the Great Sitkin volcano was also showing signs of heightened activity, the United States Geological Survey tweeted. That volcano was at an advisory level, and the color code was yellow as of Sunday. This meant the “volcano is exhibiting signs of elevated unrest above known background activity,” according to the USGS.

While the Great Sitkin volcano is showing above-average background activity, nothing noteworthy has shown up on satellite data. It had an eruption event on June 10 of this year that was fairly small and only produced a small ash deposit, according to AVO.

The Cleveland volcano has shown similar activity. There is only low-level seismic activity going on, according to the AVO. But there were above-normal surface temperatures detected by satellites. Monitoring by the seismic stations is set to continue, to follow whether the activity might become more severe at the volcano. This type of activity has historically indicated a larger explosion was on the way, Reuters reported.

If either volcano erupts, it could have the potential to impact air travel. Depending on how high the plumes from the volcanoes traveled and how strong the explosion is, the ash and smoke could cause issues for airplanes traveling over them across the Pacific, according to Reuters.

Bali Volcano Hurls Lava In New Eruption

The Mount Agung volcano on the Indonesian tourist island of Bali erupted on Monday evening, ejecting a 2000-metre-high column of thick ash and hurling lava down its slopes.

The Indonesian geological agency’s Agung monitoring post said explosions from the mountain began just after 9pm local time and lasted more than 7 minutes. “Flares of incandescent lava” reached 2 kilometres from the crater, it said, setting fire to forests at high elevation on the mountain.

It said the alert level for Agung has not been raised and the exclusion zone around the crater remains at 4km.

The National Disaster Mitigation Agency said ash was drifting west and the island’s airport, located in the south of Bali, was still operating normally. There have been no reports of injuries.

Last week, Bali’s international airport closed for half a day due to volcanic ash from Agung, disrupting travel for tens of thousands.

Monday’s eruption was “strombolian”, the geological agency said, which is the mildest type of explosive volcanic eruption. It warned people living near rivers to exercise caution, particularly in wet weather, because of the risk of fast- moving flows of muddy volcanic debris.

The volcano, about 70km north-east of Bali’s tourist hotspot of Kuta, last had a major eruption in 1963, killing about 1100 people.

It had a dramatic increase in activity last year, forcing the evacuation of tens of thousands of people, but had quietened by early this year. Authorities lowered its alert status from the highest level in February.

Indonesia, an archipelago of more than 250 million people, sits on the Pacific “Ring of Fire” and is prone to earthquakes and volcanic eruptions. Government seismologists monitor more than 120 active volcanoes.