Far field tsunami simulations of the 1755 Lisbon earthquake: Implications for tsunami hazard to the US East Coast and the Caribbean
Far field tsunami simulations of the 1755 Lisbon earthquake: Implications for tsunami hazard to the US East Coast and the Caribbean
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DOI：
10.1016/j.margeo.2008.10.010
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发表时间：
2009-08-01
期刊：
影响因子：
2.9
通讯作者：
Lin, Jian
中科院分区：
文献类型：
--
作者：
Barkan, Roy;ten Brink, Uri S.;Lin, Jian
1755 年 11 月 1 日发生的里斯本大地震，估计震级为 8.5-9.0 级，是欧洲历史上破坏性最大的地震。据报道，相关的海啸在葡萄牙和摩洛哥海岸上升了 5-15 m，其中亚速尔群岛和马德拉岛的上升幅度较大。加勒比地区、巴西和纽芬兰（加拿大）记录了跨洋海啸的预演报告。美国东海岸没有记录任何报告。为了描述 1755 年里斯本地震的震源特征，人们进行了许多尝试，包括利用地球物理调查和模拟近震强度和海啸效应。研究远控效应，如本文所述。有利于建立对震源位置和袭击方向的限制，因为跨洋海啸受近震源测深影响较小，并且不受震源处触发的海底滑坡的影响。震源位置、断层方向和测深是控制跨大西洋海啸传播到美国东海岸沿线地点的主要因素，其影响远大于距震源的距离和大陆架宽度。我们基于相对振幅比较的远场和近场海啸模拟结果将震源区域限制在位于马蹄平原中心戈林河滩以南的地区。这与之前提出的庞巴尔侯爵断层和加的斯湾断层等来源形成鲜明对比，这些断层位于马蹄平原以东。这次地震很可能是一个类似于 345 度并倾斜至 ENE 的断层上的逆冲事件，而不是建议的地震源为 NE-SW 走向的 Gorringe Bank 断层。戈林奇浅滩、马德拉-托雷海隆 (MTR) 和亚速尔群岛似乎充当了海啸能量的地形散射体，使美国东海岸的大部分地区免受 1755 年里斯本海啸的影响。评估未来亚速尔-伊比利亚板块边界沿线可能发生的地震对美国东海岸的海啸危害的额外模拟表明，MTR以西和加的斯湾的震源可能会影响美国东南海岸。MTR以西的亚速尔-伊比利亚板块边界的特征是走滑断层，而不是逆冲断层，但加的斯湾可能有逆冲断层。佛罗里达州南部似乎面临来自地铁以东和戈林奇浅滩以南的污染源的风险，但它大部分受到巴哈马群岛的保护。为了验证我们的模拟结果，有必要对美国东海岸和加勒比地区进行更高分辨率的近岸测深，并对马蹄平原中西部的潜在海啸源进行详细研究。 (C) 2008 Elsevier B.V. 保留所有权利。
The great Lisbon earthquake of November 1st, 1755 with an estimated moment magnitude of 8.5-9.0 was the most destructive earthquake in European history. The associated tsunami run-up was reported to have reached 5-15 m along the Portuguese and Moroccan coasts and the run-up was significant at the Azores and Madeira Island. Run-up reports from a trans-oceanic tsunami were documented in the Caribbean, Brazil and Newfoundland (Canada). No reports were documented along the U.S. East Coast. Many attempts have been made to characterize the 1755 Lisbon earthquake source using geophysical surveys and modeling the near-held earthquake intensity and tsunami effects. Studying far held effects, as presented in this paper. is advantageous in establishing constraints on source location and strike orientation because trans-oceanic tsunamis are less influenced by near source bathymetry and are unaffected by triggered submarine landslides at the source. Source location, fault orientation and bathymetry are the main elements governing transatlantic tsunami propagation to sites along the U.S. East Coast, much more than distance from the source and continental shelf width. Results of our far and near-field tsunami simulations based on relative amplitude comparison limit the earthquake source area to a region located south of the Gorringe Bank in the center of the Horseshoe Plain. This is in contrast with previously suggested sources such as Marques de Pombal Fault, and Gulf of Cadiz Fault, which are farther east of the Horseshoe Plain. The earthquake was likely to be a thrust event on a fault striking similar to 345 degrees and dipping to the ENE as opposed to the suggested earthquake source of the Gorringe Bank Fault, which trends NE-SW. Gorringe Bank, the Madeira-Tore Rise (MTR), and the Azores appear to have acted as topographic scatterers for tsunami energy, shielding most of the U.S. East Coast from the 1755 Lisbon tsunami. Additional simulations to assess tsunami hazard to the U.S. East Coast from possible future earthquakes along the Azores-Iberia plate boundary indicate that sources west of the MTR and in the Gulf of Cadiz may affect the southeastern coast of the U.S. The Azores-Iberia plate boundary west of the MTR is characterized by strike-slip faults, not thrusts, but the Gulf of Cadiz may have thrust faults. Southern Florida seems to be at risk from sources located east of MTR and South of the Gorringe Bank, but it is mostly shielded by the Bahamas. Higher resolution near-shore bathymetry along the U.S. East Coast and the Caribbean as well as a detailed study of potential tsunami sources in the central west part of the Horseshoe Plain are necessary to verify our simulation results. (C) 2008 Elsevier B.V. All rights reserved.