AGU journal highlights -- Oct. 16, 2008(/2008GL034457 3. New model may...)

3. New model may explain slow earthquakes

Scientists have long recognized that in the absence of notable earthquakes, the Earth at plate boundaries can experience slow deformation, such as nonvolcanic low-frequency tremor and aseismic creep. New monitoring technologies have enabled a closer study of such deformation, but apart from an observed proportionality between seismic moment and slip duration, little is known about how slow slip differs from ordinary earthquakes. To help explain a wide variety of observed features, such as steady moment rates and scaled energies, characteristics of tremor signals, and the migration of source locations, Ide develops a simple model of slow earthquakes. In his model, slow earthquakes are represented as shear slip on circular faults whose radius is a random variable governed by specific parameters. His results show that varying the radius of these faults could explain differences in the behavior of slow slip events worldwide, suggesting that all slow slip phenomena fundamentally follow the same mechanism.

Title: A Brownian walk model for slow earthquakes

Authors: Satoshi Ide: Department of Earth and Planetary Science, University of Tokyo, Tokyo, Japan

Source: Geophysical Research Letters (GRL) paper 10.1029/2008GL034821, 2008; http://dx.doi.org/10.1029/2008GL034821

4. Understanding hops of persistent organic pollutants over the oceans

Persistent organic pollutants are toxic, bioaccumulable, and semivolatile compounds that have been detected in all environments, even in remote, pristine regions where they have never been produced or used. To get to remote regions, these pollutants undergo long-range atmospheric transport that introduces them to the oceans, where they become integrated into the food web. Studies have suggested that when persistent organic pol
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