Seafloor seismometers monitor northern Cascadia earthquakes
Seafloor seismometers monitor northern Cascadia earthquakes
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海底地震仪监测卡斯卡迪亚北部地震
DOI：
10.1029/2011eo470001
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Scherwath
中科院分区：
文献类型：
--
作者：
Fumio Iida,Toru Yamamori;Yannick Vanderborght;Yuki Sekine;Takashi Suganuma;Aya K. Abe;Hayato Kobayashi;Kaori Katada;Junko Yamashita;Sakura Furukubo;Julia Obinger;Yoshio Itaba;Rie Takamatsu;Shinji Murakami;Hiroya Hirano;平原聡・岡田知己・飯尾能久・Richard H. Sibson・松本聡・Jarg Pettinga・Stephen Bannister・John Townend・Martin Reyners・Francesca C Ghisetti・小菅正裕・深畑幸俊・濱田勇輝・三浦勉・中元真美・中山貴史・大見士朗・高田陽一郎・山田真澄・米田格;Scherwath
2011 年 3 月 11 日日本海沟发生的 Mw= 9.0 级地震及其毁灭性海啸强调了了解俯冲断层的发震行为以及实际估计未来地震和海啸的潜在规模的重要性。对于卡斯卡迪亚俯冲带（图1a），一个关键的知识差距是近海微震活动水平，特别是在巨型逆冲断层附近，需要更好地了解锁定带的状态。 2010 年，沿着卡斯卡迪亚俯冲带北部进行的第一次详细海底地震监测活动记录了附近震级 (ML) 范围可能在 0 到 3.8 级之间的地震（图 1b 和 1c）以及来自该区域以外的较大地震。初步分析表明，网络似乎已经为 ML> 1.2 的事件生成了相当完整的目录。只有几十起此类事件发生在大陆架和大陆坡下方（图 1a）。大多数地震发生在努特卡边缘垂直断层带上。远离努特卡断层的相对较低的地震活动与完全锁定的巨型逆冲断层一致。陆基GPS测量无法解决巨型逆冲震源的近海部分是狭窄且完全锁定还是较宽且仅部分锁定（缓慢蠕动）的问题。如果它只是部分锁定，海底地震仪数据应该显示沿界面发生的小地震比实际检测到的多得多。
TheMw= 9.0 earthquake of 11 March 2011 at the Japan Trench and its devastating tsunami underscore the importance of understanding seismogenic behavior of subduction faults and realistically estimating the potential size of future earthquakes and tsunamis. For the Cascadia subduction zone (Figure 1a), a critical knowledge gap is the level of microseismicity offshore, especially near the megathrust, needed to better understand the state of the locked zone. In 2010 the first detailed seafloor earthquake monitoring campaign along the northern Cascadia subduction zone recorded nearby earthquakes in the local magnitude (ML) range from possibly around zero to 3.8 (Figures 1b and 1c) and larger earthquakes from outside this region. Preliminary analyses indicate that the network appears to have yielded a fairly complete catalog for events withML> 1.2. Only a few tens of these events occurred beneath the continental shelf and slope (Figure 1a). The majority of the earthquakes were located along the margin‐perpendicular Nootka fault zone. The relatively low seismicity away from the Nootka fault is consistent with a fully locked megathrust. Land‐based GPS measurements cannot resolve the question of whether the offshore part of the megathrust seismogenic zone is narrow and fully locked or wider and only partially locked (slowly creeping). If it were only partially locked, the seafloor seismometer data should show many more small earthquakes along the interface than were actually detected.
与四国岛南海海槽西部沿线非均质结构有关的地震活动
影响因子：
5.2
作者：
K. Obana;S. Kodaira;Y. Kaneda
通讯作者：
Y. Kaneda