Monday, October 3, 2011

Indonesian government raises alert on Anak Krakatau volcano in Sunda Strait, West Java

The Indonesian Volcanology Center has raised the alert from level II to Level III on Anak Krakatau Mt in Sunda Srait since last Sunday of September 30, 2011 following a number of volcanic quakes and increase of solfatara zone in the mountain flank. As for info, the Center has set four levels increasing intensity of volcanic activity with level I for the lowest and level IV for the highest.

Anak Krakatau Mt is one of the most active volcanoes in Indonesia, located within the area of the older Krakatau complex now represent as Panjang, Sertang and Rakata islands. Geographically, it’s located at the position of -6.100615,105.422688. The closest cities are Lampung, Jakarta and Banten. One hundred eruptions were recorded since June 11, 1927 with recurrence intervals every 1-6 years. Since 2007, eruptions phase occur every year in this mountain. Unfortunately, seismograph and several GPS station in Anak Krakatau were buried by eruption material lately, resulting lack of observation since July 10, 2011. On September 18, 2011 the seismograph back to its normal operation and the center observe rising in activity including the occurrence of volcanic swarm with intensity of 1-4 events per minutes.

For the last four years, strombolian eruption predominate the eruption type of this volcano. The explosive eruption disperses materials in bomb, blocks, lapilli and ash size that spread in a radius of 500-1500 around the volcano.

The Center said that at the moment it was not necessary to evacuate residents on the coast line area near the Sunda Strait but asked the residents as well as tourists to keep away from the mountain. The Anak Krakatau crater area and the area within 2km from the volcano is closed to any activity.

Hot-line Information: Geological Hazard andVolcanology center of Indonesia (Pusat Vulkanologi dan Mitigasi Bencana Geologi) phone number: +62-22-7272606 and Krakatau Observatory Center: +62-254-651449.

Location map of the Anak Krakatau Mt.

Upper Figure caption: Anak Krakatau Mt. (image source: Kompas)