TY - JOUR
T1 - Far field tsunami simulations of the 1755 Lisbon earthquake
T2 - Implications for tsunami hazard to the U.S. East Coast and the Caribbean
AU - Barkan, Roy
AU - ten Brink, Uri S.
AU - Lin, Jian
N1 - Funding Information:
Propagation models were obtained using the Cornell Multi-grid Coupled Tsunami Model (developed by Liu et al., 1998 ) in the Tsunami Computational Portal; the Portal is a joint project of the Northwest Alliance for Computational Science & Engineering at Oregon State University ( www.nacse.org ) and the Artic Region Supercomputing Center ( www.arsc.edu ) at the University of Alaska-Fairbanks. We thank Dylan Keon and Harry Yeh (Oregon State University) and Tom Logan and Elena Suleimani (Arctic Region Supercomputing Center) for assistance with running the models. We would further like to thank Xiaoming Wang (Cornell University) for technical consultations and assistance, Eric Geist (U.S. Geological Survey, Menlo Park) for fruitful discussions, and Hyun-Sook Kim, Jason Chaytor, and Brian Andrews (U.S.Geological Survey, Woods Hole) for technical assistance. Paul-Louis Blanc, Institut de Radioprotection et de Sûreté Nucléaire, France, kindly provided a copy of Frishman letter from 1755. Helpful reviews by Eric Geist and Alberto Lopez, two anonymous reviewers, and Editor David Piper are gratfully acknowledged. Roy Barkan thanks the Woods Hole Oceanographic Institution Summer Student Fellowship Program for their financial support and hospitality. Roy Barkan would further like to thank Shmulik Marco (Tel Aviv University) for providing the technical means to complete this study. This study was funded by the U.S. Nuclear Regulatory Commission under NRC Job Number N6408 Physical study of tsunami sources.
PY - 2009/8/1
Y1 - 2009/8/1
N2 - 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-field earthquake intensity and tsunami effects. Studying far field 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 Marqués de Pombal Fault, and Gulf of Cádiz Fault, which are farther east of the Horseshoe Plain. The earthquake was likely to be a thrust event on a fault striking ~ 345° 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.
AB - 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-field earthquake intensity and tsunami effects. Studying far field 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 Marqués de Pombal Fault, and Gulf of Cádiz Fault, which are farther east of the Horseshoe Plain. The earthquake was likely to be a thrust event on a fault striking ~ 345° 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.
KW - 1755 Lisbon earthquake
KW - Azores-Gibraltar plate boundary
KW - Caribbean tsunami
KW - U.S. East Coast
KW - tsunami modeling
UR - http://www.scopus.com/inward/record.url?scp=67650180058&partnerID=8YFLogxK
U2 - 10.1016/j.margeo.2008.10.010
DO - 10.1016/j.margeo.2008.10.010
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AN - SCOPUS:67650180058
SN - 0025-3227
VL - 264
SP - 109
EP - 122
JO - Marine Geology
JF - Marine Geology
IS - 1-2
ER -
