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

Thursday, January 15, 2015

Indian Ocean tsunami--not 2004, but 1945

The Makran subduction zone showing the approximate
source of the earthquake (yellow) that caused
the 945 tsunami (inferred from seismogram and
coastal uplift). Sites with blue circles show locations
of tsunami fatalities. Red dots show locations of
survivors who were interviewed, and fractions
show the fraction of credible first-hand accounts
(denominator is total number interviewed). From the
article referenced in the text.
Eos, Transactions of the American Geophysical Union features an article in the December 23 issue by D.M. Kakar and others about the next-to-last devastating tsunami in the Indian Ocean (on the 10th anniversary of the most devastating 2004 tsunami). Eos, by the way, is now freely available online to everyone at Eos.org, not just members of the AGU.
     Documentation of this earthquake and tsunami was hindered by the international instabilities of World War II and British India. This article is the result of an effort to find the aging survivors of the event and gather eyewitness accounts in order to improve tsunami hazard models and awareness. 
     The earthquake that caused the tsunami was M8.1 and centered west of Karachi (Pakistan) along the Makran subduction zone where the Indian Ocean plate is subducted below the Eurasian plate at a rate of about 4 cm/year. Estimated fatalities are between 300 and 4000, most in the areas of Pakistan, Iran and Oman shown on the map, but thirteen deaths in Bombay (Mumbai). Elders in Oman, Iran, Pakistan and India were interviewed. Most were children in 1945. Although many accounts were "hearsay", others contained details assumed to be real: "For example, the shaking in Ormara brought down a stone house that entrapped one eye-witness's recently married sister. The noisy approach of a wave in Pasni cut short the predawn Fajr prayer. The sea at Konarak entered a mosque and injured some who were praying there...."
     The authors of this article hope that the eyewitness accounts can be used to constrain models of tsunami hazards, and that the eyewitness stories will help educate those who live along the shores about tsunamis.  

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