I-MAG STS Corporation
"Indonesia having a major inland volcanic eruption at the same time as a
marine earthquake with significant tsunamis is very improbable" - a senior
Indonesian geologist.
Indonesia has nearly 240 million people, about 17,500 islands and at least four
major tectonic plates - the Australian, Eurasian, Philippine and Australian.
Having plates is not so bad - being on edges of moving plates is. Indonesia has
nearly 80 known volcanoes that have erupted in historical times. In particular,
Mt. Merapi in central Java has been active on and off for 10,000 years. It has
produced more pyroclastic flows than any other volcano on Planet Earth.
Eruptions typically occur about one to five years apart. Fortunately, the magma
is poor in gas, so the events are usually less than VEI3. Most eruptions have
involved a collapse of the lava dome, pyroclastic flows that travel 6 or 7
kilometers and impressive ash clouds. There had been significant activity from
March through June of 2006. Of concern to us was the May 27th earthquake
(6.3) that killed 5400 people followed by the 7.7 earthquake on July 17 which
caused 8 meter high tsunami waves along the southern coast of Java resulting
in 5,750 deaths, 38,560 injuries and well over 500,000 people displaced.
We are NOT very optimistic that Mt. Merapi will be going back to sleep in the
near future. On the contrary, our models suggest a major eruption before 2025.
Geological time frames are notoriously imprecise - a hundred years is a
geological eye-blink. Maybe Indonesia will avoid a volcanic event with
planetary consequences like Toba or Tambora 1815. We note that Krakatau
activity has recently elevated to level 2.
There was a 6.2 earthquake on September 29 at 17:10 UTC near the southern
coast of Papua. What was troubling was it was followed by a 7.2 30 seconds
later. We were equally alarmed by the trio of quakes in nearby New Britain:
7.0 on August 4, 7.3 July 18 (13:35 UTC) and 6.9 also July 18 (13:04 UTC).