Hydrothermal temperature changes at the southern Juan de Fuca Ridge associated with MW 6.2 Blanco Transform earthquake
Hydrothermal temperature changes at the southern Juan de Fuca Ridge associated with MW 6.2 Blanco Transform earthquake
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胡安德富卡海岭南部与 MW 6.2 布兰科变换地震相关的热液温度变化
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
R. Embley
中科院分区：
文献类型：
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作者：
R. Dziak;W. Chadwick;C. Fox;R. Embley
利用2000年6月1-7日的Blanco变换地震序列，研究了变换地震活动对山脊热液喷发和山脊变换动力学的区域性影响。利用美国海军水听器记录的T波对主震(Mw 6.2)和170次前震和余震进行了定位，表明活动转换断层可能比以往的构造模型更靠南。在地震期间，两个温度探测器部署在胡安德富卡山脊南部文特1和羽流热液区域的黑烟烟囱中。这两个热液系统位于主震声学位置西北39公里处。两个探测器都显示主震后气温显著下降(0.8摄氏度)，Vent1的温度变化发生在几天到几周的时间里，而羽流的变化是同震的。Vent1和羽流流体温度的降低与地震引起的上层洋壳渗透率的变化是一致的。证据表明，深海热液系统即使在很远的距离和跨越构造省的大地震也可以改变，而脊峰地震和岩浆活动并不是改变热液系统的唯一原因。
The regional impact of transform seismicity on ridge-crest hydrothermal venting and ridge-transform dynamics is investigated using a June 1‐7, 2000, Blanco Transform earthquake sequence. The mainshock (Mw 6.2) and 170 foreshocks and aftershocks were located using T waves recorded on U.S. Navy hydrophones, and indicate that the active transform fault may be farther south than in previous tectonic models. During the earthquake sequence, two temperature probes were deployed in black smoker chimneys at the Vent1 and Plume hydrothermal fields along the southern Juan de Fuca Ridge. These two hydrothermal systems are ;39 km northwest of the mainshock’s acoustic location. Both probes show significant (.5 8C) temperature declines following the mainshock, the Vent1 temperature changes occurring over days to weeks while the Plume changes were coseismic. The Vent1 and Plume fluid temperature decreases are consistent with earthquakeinduced changes to permeability in the upper ocean crust. The evidence suggests that deep-ocean hydrothermal systems can be altered by large earthquakes even at a distance and across tectonic provinces, and ridge-crest seismic and magmatic activity are not the only causes of change to hydrothermal systems.