Reston, Va., April 19, 2011—The March 11, 2011, earthquake off the coast of Japan measured 9.0 magnitude and triggered a major tsunami which inundated approximately 470 square kilometers in northeastern Japan. Damage is estimated at over $309 billion. According to the Oregon Department of Geology and Mineral Industries, this event is virtually a mirror image of what might occur when the next major earthquake occurs on the Cascadia Subduction Zone off the West Coast of the U.S. Inundation of the Washington, Oregon and Northern California coastlines could occur within 15 minutes of the earthquake.
Seven technical disaster assessment teams from the American Society of Civil Engineers (ASCE) will travel to Japan over the next several weeks to study the impact of the earthquake and tsunami on the region’s infrastructure, public safety and to document the lessons learned and to disseminate that knowledge to the civil engineering profession. Because of the industrialized and densely populated nature of the Honshu Tohoku coastline, and the similarity between Japanese and U.S. building codes, lessons from this tsunami will be immediately relevant to the U.S. West Coast, Alaska, Hawaii, and Canada.
ASCE publishes the standard, ASCE 7 Minimum Design Loads (weight) for Buildings and Other Structures, which is widely referenced by international building codes. ASCE recently established a committee to author a new chapter for the 2016 edition of its ASCE 7 standard that will provide prescriptive loads for tsunami and its effects. Currently, all coastal flood minimum design standards for buildings and other structures are based on hurricane conditions and these have never been evaluated for tsunami wave conditions. Thus, the knowledge to be gained by this damage assessment will directly influence international codes and standards related to civil engineering.
Engineers will examine the performance of systems such as drinking water, sewage, roads, power supplies, shore protection, coastal management efforts, ports and harbor structures, dams and embankments, telecommunications and other impacts associated with the two events. A brief overview of the mission of each team is presented below.
Structural Engineering Tsunami Effects Team: This team will document the performance of buildings and other structures not addressed by other teams. The team will concentrate in Miyagi and Iwate Prefectures along the Tohoku Coastline of Japan, with the specific focus on how this experience can be incorporated into the tsunami structural design provisions that are under development for ASCE’s Minimum Design Standards for Buildings and Other Structures. This field reconnaissance will help resolve some key questions in the tsunami design provisions regarding flow velocities and momentum of tsunami surges over land, debris flow, debris strike effects, and scouring, as well as gain information on overarching questions on risk-based design criteria and the ultimate capabilities of structures to resist a maximum credible tsunami. Deployment: This team deployed over the weekend and is posting a diary on ASCE’s website: http://cms.asce.org/PPLContent.aspx?id=12884906227
Coastal Engineering Team: Japan has relied heavily upon seawalls and shore protection to protect coastal communities and has been the leader in the construction of tsunami barriers, tsunami walls and vertical evacuation buildings for protection from tsunami events. Communities in the U.S. have been interested in some of these structures, especially the vertical evacuation shelters. This team will focus on the design and construction of breakwaters and coastal protection structures as well as the siting and design of tsunami structures, with an emphasis on the lessons learned from failures and successes alike. Tentative deployment: May 11, 2011.
Ports and Harbors Team: While loss of equipment and cargo at the ports is visible from satellite imagery, some Japanese port structures do not appear to have suffered catastrophic damage compared to the surrounding community. The team will focus on the design and construction of these structures, with an emphasis on the lessons learned from successes and failures alike. Impact to warehouses, cranes, tanks and piping systems will be directly applicable to similar U.S. facilities and the correlation of port structures and ancillary equipment damage levels and operational down-time will better define the risk and the potential loss in the U.S. Tentative Deployment: May 11, 2011
Critical Infrastructure Team: The critical infrastructure team will study the performance of all critical infrastructure including water, wastewater, power (primarily power distribution, not generation), telecommunications, airports, roads, bridges and hospitals. They will also cover emergency response and recovery times. Deployment: No Date Set.
Dams and Embankments Team: This team will focus upon the seismic performance of earth and rock fill dams, embankments, levees, and natural or modified slopes (e.g., slopes adjacent to highways). Colleagues in Japan indicate that a number of slope failures occurred during the earthquake. The team’s work will consider both the distribution and characteristics of these failures as well as their consequences. Also to be documented are the effects on associated infrastructure (e.g., highways, rail lines, structures, pipelines), dam failures (e.g., Fujinuma Dam), and dam distress (various level of cracking has been reported in 11 dams). Deployment: No Date Set.
Industrial Structures Team: This team will focus on the performance of non-building structures in many of the industrial facilities (refineries, steel mills, LNG import terminals, etc.) located near Tokyo and Sendai. The main focus will be on non-building structures similar to those in use in the U.S. and for whom the seismic design and detailing requirements are contained within ASCE’s Minimum Design Standards for Buildings and Other Structures. Deployment: No Date Set.
Nuclear Structures Team: This team will observe and document the performance of nuclear structures, systems and components, primarily nuclear power generating stations in and around the epicentral region (Fukushima Daiini station, Fukushima Daiichi station, and the Onagawa station). The main focus will be on collection of data regarding the performance of structures, systems and components to the ground shaking. Deployment: No Date Set.
Founded in 1852, the American Society of Civil Engineers represents more than 140,000 civil engineers worldwide and is America’s oldest national engineering society. For more information, visit www.asce.org.