Two volcanoes have recently come to life in Indonesia, with geologists tying the activity into the massive earthquakes that hit in December and again last month. One of the volcanoes is rattling the island hardest hit by the December quake and the tsunami it created.
The most serious eruption is that of Mount Talang, on Sumatra island, which blew ash and rocks high into the sky when it erupted Tuesday, dumping more than 20 centimeters of ash on surrounding villages and prompting the evacuation of some 26,000 people.
It was still rumbling Wednesday morning, prompting officials to raise the alert level.
The other volcano, Mount Tangkuban Perahu, about 1,500 kilometers south on Java island, has not erupted, but geologists have been recording increasing activity and have declared the surrounding area off limits.
Indonesia is one of the most geologically active regions in the world. It sits astride the intersection of three of the continent-sized tectonic plates that form the earth's crust.
Although the country is no stranger to eruptions - there are more than 130 active volcanoes in Indonesia - geologists believe the recent outburst of activity is tied to the massive earthquakes that hit in December and last month.
Surono is the head of Geological Hazard Mitigation at Indonesia's Institute of Vulcanology. "I think the effect caused by the tectonic earthquake in the west part of Sumatra. But not all the volcanoes around Sumatra, just Talang - maybe because Talang, the pressure under the volcano is high enough," he said. "So this is very simply triggered by energy released by the tectonic earthquake can trigger an eruption like that."
The area around Mount Talang has been hit by several moderate earthquakes in the past few days, frightening people who are still jittery after the massive December quake and tsunami that hit one thousand kilometers away in northern Sumatra. In addition, last month an 8.7 magnitude quake devastated the island Nias, just off the Sumatran coast.
More than 220,000 people in Indonesia were killed by those two disasters, and seismologists think continuing movement in the tectonic plates could trigger more quakes and volcanic eruptions.
There also are fears that if Mount Tangkuban Perahu does erupt, it could upset the Asia-Africa summit, where the leaders of more than 50 nations are expected to meet in nearby Bandung later this month.