Microearthquake seismicity of the Mid‐Atlantic Ridge at 5°S: A view of tectonic extension
Microearthquake seismicity of the Mid‐Atlantic Ridge at 5°S: A view of tectonic extension
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南纬 5°大西洋中脊的微地震活动：构造伸展的观点
DOI：
10.1029/2003jb002827
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发表时间：
2004
影响因子：
--
通讯作者：
W. Weinrebe
中科院分区：
文献类型：
--
作者：
F. Tilmann;E. Flueh;L. Planert;T. Reston;W. Weinrebe
我们报告的测量与海底阵列，这是操作了10天的大西洋中脊南部的5°S转换断层/断裂带。共记录到148次震级为0.5-2.8的可定位地震;地震活动似乎集中在中央山谷的西半部。中央谷地震带沿轴向北以转换断层为界，南以轴向火山脊尖为界。在转换断层上的内角高内和靠近段中心的西侧壁内发生了一些分散的地震。地震的最大深度为中央谷底以下8公里，似乎主要发生在地幔中，尽管也发生了一些地壳地震。地幔中地震的存在表明它没有强烈的蛇纹化。我们推断中谷地震活动主要源于正断层作用。
We report measurements made with an ocean bottom array which was operated for 10 days on the Mid-Atlantic Ridge just south of the 5°S transform fault/fracture zone. A total of 148 locatable earthquakes with magnitudes ∼0.5–2.8 were recorded; seismic activity appears to be concentrated within the western half of the median valley. The median valley seismic zone is bounded in along-axis direction by the transform fault to the north and the tip of the axial volcanic ridge to the south. A few scattered events occurred within the inside corner high, on the transform fault, and in the western sidewall close to the segment center. Earthquakes reach a maximum depth of 8 km below the median valley floor and appear to be predominantly in the mantle, although a few crustal earthquakes also occurred. The presence of earthquakes in the mantle indicates that it is not strongly serpentinized. We infer the median valley seismic activity to primarily arise from normal faulting.