期刊
EARTH AND PLANETARY SCIENCE LETTERS
卷 238, 期 1-2, 页码 189-203出版社
ELSEVIER
DOI: 10.1016/j.epsl.2005.06.055
关键词
creep; earthquake; seismic tremor; fluid flow; Costa Rica
Continuous measurements of fluid flow were made over a six month period across the Nicoya Peninsula, Costa Rica (Pacific), convergent margin utilizing osmotically-driven fluid flow meters designed to quantify both inflow and outflow rates on the order of similar to 10(-5) to 3 cm/d. Significant transience in flow was observed through the surface of the forearc. Three periods of correlated flow signals were seen on the subduction forearc among three instruments located in the out-of-sequence thrust (OOST) zone over along-margin strike distances of similar to 30 km. Amplitudes of ground velocity recorded on collocated ocean bottom seismometers (OBS) increase during the three correlated flow events. The seismic signal has frequency characteristics that resemble volcanic and non-volcanic tremor. We hypothesize that repeated plate boundary slow slip events, potentially originating at the up dip limit of the seismogenic zone, generate the observed signals within the toe of the forearc. We propose a model in which the poro-elastic stress/strain field around a series of creep dislocations simultaneously forces flow through fracture networks in the forearc and oceanic basement rocks and induces diffuse flow through the shallow sediments. The former generates the seismic tremor-like noise recorded by the OBSs and the latter generates the flow transients recorded by the fluid flow meters. We suggest that high sensitivity fluid flow meters can be utilized to detect transient tectonic strain events in offshore environments where traditional geodetic techniques lack resolution or are not possible. (c) 2005 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据