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Research Stories

BRUDZINKSI PART OF GREAT SUMATRA-ANDAMAN EARTHQUAKE RESEARCH

OXFORD, Ohio – Michael Brudzinski, Miami University assistant professor of geology, is a co-author of a research article in Science magazine on the great Sumatra-Andaman earthquake of December 26, 2004, that makes use of first-time available seismic data. The article is part of a special section on the quake in the May 20 issue.

The earthquake, which generated the most devastating tsunami in recorded history, was so powerful that the ground shook everywhere on the Earth’s surface and weeks later the planet still trembled. The article cites more than 150 aftershock earthquakes of magnitude 5 or greater occurring Jan. 27-30 in the Andaman Sea basin.

The December earthquake, and another remarkably great earthquake on March 28, 2005, together ruptured a 1600-kilometer-long portion of the fault boundary – the longest fault rupture ever observed - between the Indo-Australian and southeastern Eurasian plates.

“When a plate grinds beneath another plate in subduction zones like this, it creates all kinds of dangerous hazards like great earthquakes, volcanoes and tsunamis,” said Brudzinski.

The Sumatra-Andaman quakes are the largest to occur after global deployment of digital seismic instruments, providing scientists for the first time with comprehensive data for great earthquakes. Brudzinski and his colleagues used the seismogram data set from the international Federation of Digital Seismic Networks to study the surprisingly complex faulting in these earthquakes.

Among their findings is that the age of the oceanic plates increases from about 60,000 to 90,000 years between Sumatra and the Andaman Islands, which may influence the nature of the faulting. Improved tsunami-warning capabilities in the Indian Ocean, are warranted, say the authors, given the inevitability of future great earthquakes along the Sumatra subduction zone.

research interests include the processes that generate earthquakes, both near the Earth’s surface and deep within the planet, as well as the impact of experiential learning in geoscience education.

Next summer, he plans to offer a field workshop in southern Mexico for Miami students to learn first-hand how geologists study the nature of hazards in subduction zones.