Pure and Applied Geophysics

, Volume 170, Issue 6, pp 1189–1206

Coastal Impacts of the March 11th Tohoku, Japan Tsunami in the Galapagos Islands

  • Patrick Lynett
  • Robert Weiss
  • Willington Renteria
  • Giorgio De La Torre Morales
  • Sangyoung Son
  • Maria Elizabeth Martin Arcos
  • Breanyn Tiel MacInnes
Article

DOI: 10.1007/s00024-012-0568-3

Cite this article as:
Lynett, P., Weiss, R., Renteria, W. et al. Pure Appl. Geophys. (2013) 170: 1189. doi:10.1007/s00024-012-0568-3

Abstract

On March 11, 2011 at 5:46:23 UTC (March 10 11:46:23 PM Galapagos Local Time), the Mw 9.0 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.

Copyright information

© Springer Basel AG 2012

Authors and Affiliations

  • Patrick Lynett
    • 1
  • Robert Weiss
    • 2
  • Willington Renteria
    • 3
  • Giorgio De La Torre Morales
    • 3
  • Sangyoung Son
    • 1
  • Maria Elizabeth Martin Arcos
    • 4
    • 5
  • Breanyn Tiel MacInnes
    • 5
    • 6
  1. 1.Department of Civil and Environmental EngineeringUniversity of Southern CaliforniaLos AngelesUSA
  2. 2.Department of GeosciencesVirginia TechBlacksburgUSA
  3. 3.Coastal and Environmental Studies SectionInsitituto Oceanográfico de la Armada Guayaquil (INOCAR)Galapagos IslandsEcuador
  4. 4.AMECOaklandUSA
  5. 5.Department of Earth and Space SciencesUniversity of WashingtonSeattleUSA
  6. 6.Institute of Seismology and VolcanologyHokkaido UniversityHokkaidoJapan

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