Lessons Likely for the U.S. Northwest
ASCE’s fourth reconnaissance team to investigate infrastructure damage in Japan caused by the March 11 earthquake and tsunami is at the scene. This team, sponsored by the Coasts, Oceans, Ports, and Rivers Institute, is investigating the effect on coastal structures such as tsunami walls, breakwaters and seawalls that are used for navigation, flood control and life safety. It is being led by Lesley Ewing, P.E., D.CE, M.ASCE, a senior coastal engineer with the California Coastal Commission, based in San Francisco. Ewing and/or her teammates will be providing updates on their findings and experiences in regular posts.
Read each day's entries:
Day 1-2 | Day 3 | Day 4 | Day 5 | Day 6 | Day 7
Days 1 and 2 -- Wednesday, May 11 and Thursday, May 12
The Coastal Structures and Coastal Management team will be in Japan from May 10 through May 18, investigating the performance of coastal structures and coastal management efforts from the March 11 Tohoku Oki earthquake and tsunami. The team is made up of members from the Coasts, Oceans, Ports, and Rivers Institute of ASCE and from the Ports and Airports Research Institute (PARI) in Japan. The COPRI team members are Lesley Ewing, P.E., D.CE, M.ASCE, of the California Coastal Commission; Bryan Jones, P.E., M.ASCE, of the Ocean and Coastal Consultants of COWI; James Marino, P.E., D.CE, M.ASCE, of Coastal Tech; Ron Noble, P.E., D.CE, D.PE, M.ASCE, of Noble Consultants; and Dr. Catherine Petroff, Ph.D, P.E. of LP4 Associates and the University of Washington. The PARI team members are Drs. Shigeo Takahashi, Tanaka, and Suzuki, and Dr. Kojima of Kyushu Kyoristu Univerity.
Over the six days in the field, the team will travel from Misawa to Sendai, visiting fishing ports, harbors, and coastal communities, with a focus on which structures or natural features provided protection to the inland areas; why certain protective structures or protective features survived the tsunami with little or no damage, and why others suffered complete destruction or were not effective in providing any noticeable level of protection to the inland community.
The Coastal Structures team spent its first full day in Japan attending meetings and getting to know each other. In the morning, we had the opportunity to meet with Daniel T. Cox, Ph.D., past director of the O.H. Hinsdale Wave Research Laboratory at Oregon State University, who had already traveled to the Tohoku area with the second group of the ASCE 7 survey team. In the afternoon, we attended a seminar organized by PARI to cover many of the key research findings from the Japanese researchers who had been examining the effects of the tsunami over the past two months.
Cox has been on sabbatical at Kyoto University for the past six months studying tsunamis with DPRI, a disaster risk management institute. With his home in Oregon, he spent some time talking about the similarities and dissimilarities between the U.S. Pacific Northwest and the Tohoku coast. Since the Cascadia Subduction Zone off the coast of northern California, Oregon, and Washington is the U.S. fault zone most similar to the source of the Tohoku Oki Earthquake and tsunami, these comparisons are important to recognize. Both seem to be mountainous coasts with isolated coastal communities and people place heavy reliance upon fishing. Japan is a country that is very creative with ways to enjoy seafood and about 50% of the domestic eatable fish come from the Tohoku area.
As we learned in an afternoon seminar prepared by PARI, 319 fishing ports were damaged by the tsunami at an estimated cost of ¥93 billion; 18,936 fishing vessels are damaged or lost, with an additional cost of ¥123.7 billion. There is some general agreement that the harbors provided some protection for the inland areas when compared with the unprotected areas adjacent to the ports.
Takahashi discussed some modeling work completed recently for the earthquake-tsunami event. One of his examples was from Kamaishi, where the harbor is protected by southern and northern breakwaters with a 30-meter gap. The breakwaters were designed and built over a 20-year period, using normal storm wave conditions; no tsunami waves were included in the design. Although these breakwaters suffered significant damage during the tsunami, modeling indicates that the inland inundation was almost six meters less than what would have occurred without the breakwaters (the community experienced eight meters with the breakwater, but would likely have had 13.8 meters without the structures). Similar but less dramatic decreases in inundation occurred at Ofunato.
Following the seminar and congenial dinner with several colleagues from the seminar, we prepare for an early morning flight to Misawa. From there we will start our own investigation, hoping to see many other examples of success or partial success from which to learn how to make coastal communities more resilient to future disasters while maintaining the major functions and attributes that attract people and industry to the coast. The next blog will be from the Tohoku region and will include photos of the areas.
Day 1-2 | Day 3 | Day 4 | Day 5 | Day 6 | Day 7