Coastal Impacts of the March 11th Tohoku, Japan Tsunami in the Galapagos Islands
Coastal Impacts of the March 11th Tohoku, Japan Tsunami in the Galapagos Islands
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3 月 11 日日本东北海啸对加拉帕戈斯群岛沿海的影响
DOI：
10.1007/s00024-012-0568-3
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发表时间：
2012
影响因子：
2
通讯作者：
B.T.
中科院分区：
文献类型：
--
作者：
Lynett;P.;Weiss;R.;Renteria;W.;Morales;G.D.L.T.;Son;S.;Arcos;M.E.M. and Maclnnes;B.T.
2011年3月11日5：46：23 UTC（当地时间3月10日11：46：23 PM加拉帕戈斯），东日本大地震发生在日本东海岸东北地区附近，引发了太平洋海啸。大约12，000公里外的加拉帕戈斯群岛遭受了中度海啸影响，包括洪水、结构破坏和强海流。在本文中，我们提出的意见和测量海啸的影响，在加拉帕戈斯，重点是四个最大的岛屿在群岛;（从西到东）伊萨贝拉，马拉加焦，圣克鲁斯，和圣克里斯托瓦尔。如何进入海啸灾区是实地调查的最大挑战之一。除了向游客开放的大约10个桑迪外，所有其他海岸线地点都只对没有研究许可证的人开放;与加拉帕戈斯国家公园的开放合作使调查小组能够完全进入群岛的海岸线。在实地工作之前，对海啸进行了数值模拟，以此指导调查地点。这一数值指导准确地预测了影响最大的地区以及影响相对较低的地区。潮汐校正的最大海啸高度一般在3-4米范围内，在伊萨贝拉岛的一个小口袋海滩测得的最高爬高为6米。位于加拉帕戈斯最大港口圣克鲁斯岛的阿约拉港经历了严重的洪水泛滥，海岸线上的建筑物遭到破坏。一个停泊在港口内的海流计记录到了相对较弱的海啸海流，低于0.3米/秒（0.6节）。详细的数值模拟的比较表明，这些低流速观测结果最有可能是平均在20分钟的时间间隔，最大瞬时流速相当大的数据。圣克鲁斯岛和近海一个较小岛屿之间的天然水道伊塔巴卡运河的水流强大到足以使多个5.5吨重的导航浮标移位。数值模拟表明，伊塔巴卡运河的水流速度超过4米/秒（约8节），这是一个非常大的航行水道流速。
On March 11, 2011 at 5:46:23 UTC (March 10 11:46:23 PM Galapagos Local Time), the Mw9.0 Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan, spawning a Pacific-wide tsunami. Approximately 12,000 km away, the Galapagos Islands experienced moderate tsunami impacts, including flooding, structural damage, and strong currents. In this paper, we present observations and measurements of the tsunami effects in the Galapagos, focusing on the four largest islands in the archipelago; (from west to east) Isabela, Santiagio, Santa Cruz, and San Cristobal. Access to the tsunami affected areas was one of the largest challenges of the field survey. Aside from approximately ten sandy beaches open to tourists, all other shoreline locations are restricted to anyone without a research permit; open cooperation with the Galapagos National Park provided the survey team complete access to the Islands coastlines. Survey locations were guided by numerical simulations of the tsunami performed prior to the field work. This numerical guidance accurately predicted the regions of highest impact, as well as regions of relatively low impact. Tide-corrected maximum tsunami heights were generally in the range of 3–4 m with the highest runup of 6 m measured in a small pocket beach on Isla Isabela. Puerto Ayora, on Santa Cruz Island, the largest harbor in the Galapagos experienced significant flooding and damage to structures located at the shoreline. A current meter moored inside the harbor recorded relatively weak tsunami currents of less than 0.3 m/s (0.6 knot) during the event. Comparisons with detailed numerical simulations suggest that these low current speed observations are most likely the result of data averaging at 20-min intervals and that maximum instantaneous current speeds were considerably larger. Currents in the Canal de Itabaca, a natural waterway between Santa Cruz Island and a smaller island offshore, were strong enough to displace multiple 5.5-ton navigation buoys. Numerical simulations indicate that currents in the Canal de Itabaca exceeded 4 m/s (~8 knots), a very large flow speed for a navigational waterway.