This blog provides commentary on interesting geological events occurring around the world in the context of my own work. This work is, broadly, geological fluid dynamics. The events that I highlight here are those that resonate with my professional life and ideas, and my goal is to interpret them in the context of ideas I've developed in my research. The blog does not represent any particular research agenda. It is written on a personal basis and does not seek to represent the University of Illinois, where I am a professor of geology and physics. Enjoy Geology in Motion! I would be glad to be alerted to geologic events of interest to post here! I hope that this blog can provide current event materials that will make geology come alive.

Banner image is by Ludie Cochrane..

Susan Kieffer can be contacted at s1kieffer at gmail.com

Tuesday, July 2, 2013

M6.1 earthquake strikes Indonesia's Aceh province

     In 2004, an earthquake of estimated magnitude 9.1-9.3 off Aceh province in Indonesia triggered a tsunami that killed an estimated 230,000 people around the Pacific Rim in Asia. Today a much smaller, M6.1 struck, killing at least one person (possibly many more, news reports are still coming in), leaving two others missing, dozens injured, and several dozen homes damaged. The earthquake caused at least one landslide.
Map of Indonesia; the red square near Jakarta shows the
location of the 2012 M8.2 aftershock
From this site.
Today's M6.1 quake was at about 1:00 to the NE of the
epicenter of the 2004 quake (shown as the big
bull's eye on the left) in the center of the tip of
     This is not the largest earthquake to hit Indonesia since the 2004 event; one quake, centered beneath the ocean floor and roughly 300 miles from Banda Aceh (the capital of Aceh province), was a M8.6. It was followed by a M8.2 aftershock. It is humbling to remember that a relatively small earthquake like today's M6.1 kills people, and would be major news if it occurred in the U.S. That people in Indonesia live with these killer quakes all of the time should not be forgotten.
    The 2004 event was located about 100 miles off the western coast of northern Sumatra at a depth of 19 miles below sea level (today's event was, in contrast, only about 6 miles deep and was centered below land; see map and caption). A huge section of length 810 miles ruptured during this quake. The main rupture was followed by secondary faulting (dubbed "pop up faults" on Wiki" that acted in concert with the main rupture to produce the massive tsunami that caused so much destruction around the Asian Pacific Rim. The total length of all of the faulting, which took place over several minutes, was about 1000 miles.

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