AGU journal highlights -- Aug. 1, 2007

Title: Antarctic deglacial pattern in a 30 kyr record of sea surface temperature offshore South Australia

Authors: Eva Calvo: Institut de Ciències den Mar, Consejo Superior de Investigaciones Científicas, Barcelona, Spain;

Carles Pelejero: Institució Catalana de Recerca i Estudis Avançats and Institut de Ciències den Mar, Consejo Superior de Investigaciones Científicas, Barcelona, Spain;

Patrick De Deckker: Department of Earth and Marine Sciences, The Australian National University, Canberra, Australia;

Graham A. Logan: Petroleum and Marine Division, Geoscience Australia, Canberra, Australia.

Source: Geophysical Research Letters (GRL) paper 10.1029/2007GL029937, 2007

9. Aseismic creep in Mexico

During an earthquake, friction between plates is released suddenly, causing the ground to rumble. However, during aseismic slow slip events, tension along faults is released gradually, causing plates to creep. First reported in the late 1990s, aseismic creep is of interest to scientists seeking to understand plate movement and seismic hazards. Through a network of GPS receivers, Larson et al. study an aseismic slow slip event that occurred from April to December 2006 in southern Mexico. This network includes a 275 kilometer (171 miles) transect extending from the coast to Mexico City and a swath that spans 75 kilometers (47 miles) along the coast parallel to the Middle America Trench, a subduction zone where the Cocos Plate is sinking under North America. The authors find that this event generated horizontal displacements of nearly 6 centimeters in the direction opposite to that recorded by earthquakes. Using this data, they model the aseismic creep and find that slip was concentrated on interior fault patches in the subduction zone. Energy released by this event had a minimum equivalent of magnitude 7.5.

Title: 2006 aseismic slow slip event in Guerrero, Mexico: New results from GPS

Authors: Kristine M. Larson: Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, Colorado, U.S.A.;

Vladimir Kostoglodov and Jose Antonio Santiago Santiago: Instituto de Geofisica, Universidad Nacional Autónoma de México, Mexico City, Mexico;

Shin’ichi Miyazaki: Earthquake Research Institute, University of Tokyo, Tokyo, Japan.

Source: Geophysical Research Letters (GRL) paper 10.1029/2007GL029912, 2007

10. Plasma-depleted flux tubes in Saturn's inner magnetosphere