The following essay is available for re-publication in The Conversation.
The eruption of Mount Semeru in Indonesia on Saturday claimed the lives of 22 people, with another 22 still missing and 56 injured. More than 5,000 people have been affected by the eruption, and more than 2,000 people have taken refuge.
The Saturday eruption produced an ash cloud that reached 15 km into the atmosphere, along with hot pyroclastic flows. Lahars are volcanic mudflows that fall down the volcano's steep slopes. The villages were blanketed in heavy ash and some areas were dark.
Several villages have been buried in up to 4 metres of volcanic material and debris, more than 3000 buildings have been damaged, and the Gladak Perak Bridge has collapsed.
Jembatan Gladak Perak penghubung.
Gunung Semeru hari ini, ini, wasa, wasa, wasa, wasa, wasa, wasa, wasa, wasa, wasa, wasa, wasa, wasa, wasa, wasa, wasa, was
December 4, 2021.
The volcano observatory has reported that ash is reaching 4.5 km above the summit and that further pyroclastic flows are travelling down the volcano's slopes. There are reports of lava flows at the summit crater.
In the past 80 years, activity has taken place on Mt. Semeru, one of the most active volcanoes in Java. The current eruptive phase began in 2014, with frequent emissions of ash to hundreds of metres above the crater.
Unexpected large-scale eruption.
Saturday's eruption was much larger than the current activity. The head of the Geological Agency of the Ministry of Energy and Mineral Resources said a storm and rain had eroded part of the volcano's lava dome. The dome collapsed due to this.
Some of the deadliest eruptions in history have been caused by lava collapse dome eruptions. The collapse of the dome of solidified lava is similar to taking the top off a bottle of water and causing an eruption. The Mt. Semeru lava domes were weakened by external weather conditions as they grew.
The fact that Saturday's eruption was triggered by an external factor, rather than conditions inside the volcano, would have made this event harder to forecast.
Increased unrest inside a volcano is a sign of increased volcano monitoring. Increased earthquake activity can be a sign that the ground is moving. A change in the temperature or type of gases is a warning sign. Sometimes, small changes in the shape of the volcano can be seen on the ground or from satellites.
There was an explosion in New Zealand in 2019. The event was thought to have been driven by an explosion of steam rather than magma, which made it difficult to predict.
Living with active volcanoes.
People are living close to active volcanoes as the world population grows. One estimate states that more than a billion people live within 100 km of an active volcano.
175 million people live within 100 km of one or more of the country's 130 active volcanoes in Indonesia. More than 8 million Indonesians live within 10 km of an active volcano.
These communities need to balance their livelihoods with the risks of being near volcanoes. Indonesia's volcano monitoring and disaster management authorities face a challenge keeping an eye on dozens of active volcanoes.
The Conversation published this article. The original article can be found here.