Rick Wilson

Assessment of the tsunami‐induced current hazard

The occurrence of tsunami damage is not limited to events causing coastal inundation. Even without flooding, maritime assets are vulnerable to significant damage from strong currents and associated drag forces. While such impacts have been observed in the past, they have not been well studied in any context. Nearshore tsunami currents are governed by nonlinear and turbulent physics and often have large spatial and temporal variability making high-fidelity modeling particularly challenging. Furthermore, measured data for the validation of numerical simulations is limited, with few quality data sets appearing after recent tsunami events. In this paper, we present a systematic approach for the interpretation of measured tsunami-induced current impacts as well as a validation approach for simulation tools. The methods and results provided here lay the foundation for much needed efforts to assess tsunami hazards in ports and harbors.

New Maps of California to Improve Tsunami Preparedness

~ 6.6) the next day. Although no lives were lost in these temblors, 98 peo-ple were injured. These earthquakes heavily damaged older structures within this sparsely populated, mountainous region, causing more than US

Monte Carlo–Based Approach to Estimating Fragility Curves of Floating Docks for Small Craft Marinas

66 million in losses.Approximately 20 minutes after the fi rst earthquake, tide gauge stations in nearby Crescent City reported a surge—a tsunami with maximum wave heights (from trough to crest) of 1.1 meters. The tsunami hit Cres-cent City and Eureka at low tide. Fortunately, no damages occurred to city or harbor facil-ities—had this happened during high tide, it may have been a different story [

A protocol for coordinating post-tsunami field reconnaissance efforts in the USA

As a result of damage from the 2010 Chile and 2011 Japanese teletsunamis, tsunami risk to small craft marinas along the West Coast of the United States has become an important concern. This paper outlines an assessment tool that can be used to quantify the tsunami damage potential in small craft harbors. The methodology is based on the demand and capacity of a floating dock system and uses a Monte Carlo framework to address the uncertainty of input parameters. Detailed numerical modeling and damage calibration data from recent tsunamis are used to benchmark the approach. Results are provided as fragility curves and give a quantitative assessment of survivability. This tool yields an indication as to the survivability and/or failure of a floating dock system of vessels and floating components/piles subject to tsunami events. The objective of the presented effort is to quickly evaluate whether a floating dock is likely to survive or be destroyed by a particular tsunami scenario.DOI: 10.1061/(ASCE)WW.1943-5460.0000385.© 2017 American Society of Civil Engineers.

Intra-community implications of implementing multiple tsunami-evacuation zones in Alameda, California

In the aftermath of a catastrophic tsunami, much is to be learned about tsunami generation and propagation, landscape and ecological changes, and the response and recovery of those affected by the disaster. Knowledge of the impacted area directly helps response and relief personnel in their efforts to reach and care for survivors and for re-establishing community services. First-hand accounts of tsunami-related impacts and consequences also help researchers, practitioners, and policy makers in other parts of the world that lack recent events to better understand and manage their own societal risks posed by tsunami threats. Conducting post-tsunami surveys and disseminating useful results to decision makers in an effective, efficient, and timely manner is difficult given the logistical issues and competing demands in a post-disaster environment. To facilitate better coordination of field-data collection and dissemination of results, a protocol for coordinating post-tsunami science surveys was developed by a multi-disciplinary group of representatives from state and federal agencies in the USA. This protocol is being incorporated into local, state, and federal post-tsunami response planning through the efforts of the Pacific Risk Management ‘Ohana, the U.S. National Tsunami Hazard Mitigation Program, and the U.S. National Plan for Disaster Impact Assessments. Although the protocol was designed to support a coordinated US post-tsunami response, we believe it could help inform post-disaster science surveys conducted elsewhere and further the discussion on how hazard researchers can most effectively operate in disaster environments.

The SAFRR Tsunami Scenario

Tsunami-evacuation planning in coastal communities is typically based on maximum evacuation zones for a single scenario or a composite of sources; however, this approach may over-evacuate a community and overly disrupt the local economy and strain emergency-service resources. To minimize the potential for future over-evacuations, multiple evacuation zones based on arrival time and inundation extent are being developed for California coastal communities. We use the coastal city of Alameda, California (USA), as a case study to explore population and evacuation implications associated with multiple tsunami-evacuation zones. We use geospatial analyses to estimate the number and type of people in each tsunami-evacuation zone and anisotropic pedestrian evacuation models to estimate pedestrian travel time out of each zone. Results demonstrate that there are tens of thousands of individuals in tsunami-evacuation zones on the two main islands of Alameda, but they will likely have sufficient time to evacuate before wave arrival. Quality of life could be impacted by the high number of government offices, schools, day-care centers, and medical offices in certain evacuation zones and by potentially high population density at one identified safe area after an evacuation. Multi-jurisdictional evacuation planning may be warranted, given that many at-risk individuals may need to evacuate to neighboring jurisdictions. The use of maximum evacuation zones for local tsunami sources may be warranted given the limited amount of available time to confidently recommend smaller zones which would result in fewer evacuees; however, this approach may also result in over-evacuation and the incorrect perception that successful evacuations are unlikely.

Observations and Impacts from the 2010 Chilean and 2011 Japanese Tsunamis in California (USA)

The U.S. Geological Survey and several partners operate a program called Science Application for Risk Reduction (SAFRR) that produces (among other things) emergency planning scenarios for natural disasters. The scenarios show how science can be used to enhance community resiliency. The SAFRR Tsunami Scenario describes potential impacts of a hypothetical, but realistic, tsunami affecting California (as well as the west coast of the United States, Alaska, and Hawaii) for the purpose of informing planning and mitigation decisions by a variety of stakeholders. The scenario begins with an Mw 9.1 earthquake off the Alaska Peninsula. With Pacific basin-wide modeling, the authors estimate up to 5m waves and 10 m/sec currents would strike California 5 hours later. In marinas and harbors, 13,000 small boats are damaged or sunk (1 in 3) at a cost of

Observed and Modeled Currents from the Tohoku-oki, Japan and other Recent Tsunamis in Northern California

350 million, causing navigation and environmental problems. Damage in the Ports of Los Angeles and Long Beach amount to

Sediment scour and deposition within harbors in California (USA), caused by the March 11, 2011 Tohoku-oki tsunami

110 million, half of it water damage to vehicles and containerized cargo. Flooding of coastal communities affects 1800 city blocks, resulting in

Inter-model analysis of tsunami-induced coastal currents

640 million in damage. The tsunami damages 12 bridge abutments and 16 lane-miles of coastal roadway, costing