June Media Highlights: Geology

Boulder, CO, USA  - Topics include: how oceans reacted to greenhouse conditions of the Cretaceous; first direct age determination of an Archean microfossil; discovery of a swimming bipedal dinosaur; understanding volcanoes that don't eject lava or debris; and new insights into the relationship of megathrust earthquakes and volcanic eruptions.

Highlights are provided below. Representatives of the media may obtain complimentary copies of articles by contacting Ann Cairns at acairns@geosociety.org. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to GEOLOGY in articles published. Contact Ann Cairns for additional information or other assistance.

Non-media requests for articles may be directed to GSA Sales and Service, gsaservice@geosociety.org.

Volcanic eruptions following M ≥ 9 megathrust earthquakes: Implications for the Sumatra-Andaman volcanoes
Thomas R. Walter, GeoForschungsZentrum, Physics of the Earth, Potsdam, GER 14473, Germany; and Falk Amelung, Department of Marine Geology and Geophysics, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, FL, USA. Pages 539-542.

The study is motivated by two volcanic eruptions in the Sumatra-Andaman arc that followed the disastrous 9.3 magnitude earthquake of 26 December 2004 and its aftershocks, reviving a century-long dispute about volcanism related to large earthquakes. Walter and Amelung analyze the four largest instrumentally recorded earthquakes and calculate the earthquake-induced strain and eruption rate changes along the nearby volcanic arcs. They show that eruptions occurred at volcanoes that experienced volumetric expansion during the preceding megathrust earthquake, suggesting that evaluation of the coseismic deformation provides an estimate of whether an earthquake increased or decreased the eruption potential of a volcano.