Geoscience Reference
In-Depth Information
Chapter1
Background
and
Scope
1.1
Introduction
The March 11, 2011, a magnitude 9.0 earthquake generated a Pacific-wide tsunami,
now known as the Tohoku Oki or Great East Japan earthquake and tsunami. Buoys
off the coast of Japan measured offshore wave heights that exceeded six meters, and
the first waves reached the northeastern coast of Japan within 25 to 30 minutes of the
seismic event. Onshore extensive inundation often exceeded the design heights of
shoreline structures. At the Fukushima Daiichi nuclear power plant, damaged reactors
released radiation and caused power outages, just two of the many consequences that
compounded the effects of the seismic event and tsunami. The earthquake caused as
much as a meter of subsidence, exacerbating the effects of the tsunami and exposing
previously dry areas to twice daily inundation from high tides.
Propagating throughout the Pacific, waves from the Great East Japan tsunami
damaged port and harbor areas in Hawaii, Oregon, and California and buildings along
the coasts of Guam and Chile; however, the greatest destruction, by far, occurred in
Japan. The tsunami inundated over 561 square kilometers (217 square miles) of land.
As of 15 July, 2011 estimated deaths from the Great East Japan earthquake and
tsunami reached 15,562, with 5,306 missing and 5,690 injured in the event. Initial
damage estimates ranged between $197 billion to $308 billion (16 trillion - 25 trillion
yen), and the event generated over 24 million tons of waste and debris (Johnson
2011; Kamiya 2011).
ASCE has supported field investigations in the wake of a number of natural and man-
made disasters. The purpose of these investigations has been to learn about the
performance and failure modes of structures as well as natural and human systems
when extreme events push them to their limits. These real-world conditions often
expose structures to extreme combinations of forces and provide very different
learning opportunities than those available through laboratory modeling or numerical
simulations. Results from these investigations can serve a variety of purposes —
model calibration and verification, improved codes and standards for manuals of
practice, and greater understanding of structural and systems performance.
In the days and weeks following the Great East Japan earthquake and tsunami, ASCE
assembled seven teams to investigate various aspects of the earthquake, tsunami, and
the Fukushima Daiichi nuclear disaster. The Coastal Engineering Structures team
comprised members from ASCE and the Coasts, Ocean, Ports and Rivers Institute
(COPRI). Japanese engineers with similar and compatible interests joined each ASCE
team in the field. Engineers who joined the COPRI Coastal Engineering Structures
team from the Port and Airport Research Institute (PARI) and Kyushu Kyoritsu
University made valuable contributions to the investigation's success. Partnerships
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