Tsunamis are caused by earthquakes or massive landslides and can inflict severe flooding in low-lying coastal areas. CMG research aims to understand the local and regional susceptibility to tsunamis, and contribute to public disaster education and preparedness.
Open-File Report 2010-1172: Database of Recent Tsunami Deposits This report describes a database of sedimentary characteristics of tsunami deposits derived from published accounts of tsunami deposit investigations conducted shortly after the occurrence of a tsunami. The database contains 228 entries... Posted: 2010-09-28
Geological Impacts and Sedimentary Record of the February 27, 2010, Chile Tsunami—La Trinchera to Concepcion The February 27, 2010, Chilean tsunami substantially altered the coastal landscape and left a permanent depositional record that may be preserved at many locales along the central coast of Chile. From April 24 to May 2, 2010, a team of U.S. Geological Survey (USGS) and Chilean scientists examined the geological impacts of the tsunami at five sites along a 200-km segment of coast centered on the earthquake epicenter. Posted: 2010-06-08
USGS Scientists in Samoa and American Samoa Studying Impacts of Recent Tsunami, October-November 2009 On September 29, 2009, a magnitude-8.0 submarine earthquake occurred at 6:48a.m. Samoa Standard Time approximately 190 km (120 mi) south of Samoa and triggered a tsunami that caused more than 100 deaths and widespread damage in Samoa, American Samoa, and Tonga. Observers reported four tsunami waves that ranged from approximately 1.5 to 6 m high and reached as far as 1.5 km inland. A rapid-response team of USGS scientists is traveling to American Samoa to collect data that will be quickly degraded or destroyed by recovery activity and natural processes. USGS Western Coastal and Marine Geology (WCMG) oceanographer Bruce Jaffe arrived in Pago Pago, on the island of Tutuila, American Samoa, on October 4 and was joined later in the week by fellow WCMG scientists Bruce Richmond, Mark Buckley, Guy Gelfenbaum, Steve Watt, and Alex Apotsos. Oceanographer Walter Dudley of the University of Hawai‘i, Hilo, will work with the USGS team. The team will collect time-sensitive data to help them determine the height of tsunami waves at various sites and the distances the waves traveled inland. They will study the transport of sediment and other debris, look for and measure evidence of subsidence and uplift caused by the earthquake, document erosion caused by the tsunami waves, and make other observations critical to the better understanding of tsunami impacts and processes. Posted: 2009-11-24
Cascadia Seismic Hazard Studies Investigations of Earthquake and Tsunami Hazards and History in the Pacific Northwest, specifically the Cascadia Subduction Zone. Posted: 2009-07-24
USGS Monterey Bay Science USGS Monterey Bay Science - USGS research in the Monterey Bay National Marine Sanctuary and coastal watersheds of central California Posted: 2008-01-01
USGS Coastal Change Hazards USGS Coastal Change Hazards - Focuses on hurricanes, tsunamis, sea-level rise, shoreline erosion, wetland destruction, and other issues relevant to coastal zone management and disaster preparedness. Posted: 2008-01-01
Coastal and Marine Knowledge Bank An initiative to develop and present a national-scale, interdisciplinary scientific framework for marine environments, the coastal zone, and coastal watersheds Posted: 2007-11-28
Investigation of the M6.6 Niigata-Chuetsu Oki, Japan, Earthquake of July 16, 2007 The M6.6 mainshock of the Niigata Chuetsu Oki (offshore) earthquake occurred at 10:13 a.m. local time on July 16, 2007, and was followed by a sequence of aftershocks that were felt during the entire time of the reconnaissance effort. The mainshock had an estimated focal depth of 10 km and struck in the Japan Sea offshore Kariwa. Analysis of waveforms from source inversion studies indicates that the event occurred along a thrust fault with a NE trend. The fault plane is either a strike of 34 degrees with a dip of 51 degrees or a strike of 238 degrees with a dip of 41 degrees. Which of these two planes is associated with the mainshock rupture is unresolved, although attenuation relationship analysis indicates that the northwest-dipping fault is favored. The quake affected an approximately 100-km-wide area along the coastal areas of southwestern Niigata prefecture. The event triggered ground failures as far as the Unouma Hills, located in central Niigata approximately 50 km from the shore and the source area of the 2004 Niigata Chuetsu earthquake. The primary event produced tsunami run-ups that reached maximum runup heights of about 20 centimeters along the shoreline of southern Niigata Prefecture. Posted: 2007-11-15
Open-File Report 2006-1293 - Reconnaissance Investigation of Caribbean Extreme Wave Deposits; Preliminary Observations, Interpretations, and Research Directions his report presents an overview of preliminary geological investigations and recommended future research activities in the Caribbean region pertaining to coastal hazards with an emphasis on establishing tsunami risk for U.S. territories. Fieldwork was conducted in March 2006 on the islands of Bonaire, Puerto Rico, and Guadeloupe to evaluate the stratigraphic records of extreme wave deposits as possible indicators of paleotsunami recurrence. Morphological, sedimentological, and stratigraphic evidence indicate that shore-parallel coral rubble deposits composed of coarse clasts and sand that are 10s of meters wide and several meters thick are depositional complexes that have accumulated for a few centuries or millennia, and are not entirely the result of one or a few tsunamis as previously reported. The origins of boulder fields on elevated rock platforms of the Caribbean islands are more complicated than the origins of ridge complexes because boulder fields can be constructed by either storm waves or tsunamis. What is needed now for more conclusive interpretations is a systematic sedimentological approach to deposit analysis and a set of criteria for distinguishing between coarse clast storm and tsunami deposits. Assembling more field data from other Caribbean islands, analyzing stratigraphic deposits on Puerto Rico and Bonaire, and investigating boulder field deposits resulting from a historical tsunami can accomplish this. Also needed are improved sediment transport models for coarse clasts that can be used to estimate the competence and capacity of tsunamis and storms waves and to determine whether a deposit likely was created by a tsunami or extreme storm. Improved models may also be useful for reconstructing the magnitude of extreme wave events. Posted: 2006-10-30
Open-File Report 2006-1234 - Seaside, Oregon Tsunami Pilot Study--Modernization of FEMA Flood Hazard Maps FEMA Flood Insurance Rate Map (FIRM) guidelines do not currently exist for conducting and incorporating tsunami hazard assessments that reflect the substantial advances in tsunami research achieved in the last two decades; this conclusion is the result of two FEMA-sponsored workshops and the associated Tsunami Focused Study. Therefore, as part of FEMA’s Map Modernization Program, a Tsunami Pilot Study was carried out in the Seaside/Gearhart, Oregon, area to develop an improved Probabilistic Tsunami Hazard Assessment (PTHA) methodology and to provide recommendations for improved tsunami hazard assessment guidelines. Posted: 2006-09-01
Tsunamis and Earthquakes - 2005 Sumatra Tsunami Study - USGS WCMG USGS Western Coastal and Marine Geology was part of an international team that studied sediment deposits in Sri Lanka from the tsunami generated by the magnitude 9.0 Sumatra earthquake on December 26, 2004. Posted: 2005-05-31
USGS WCMG - Notes from the field... Sumatra 2005 News and Information about the USGS West Sumatra International Tsunami Survey Team's Field Study, March 30 - April 26, 2005. These "Notes from the field" pages were created on a daily basis as a way to report findings during the ITST's field study. The effort began just as the 28 March 2005 earthquake and tsunami occurred off Sumatra. Posted: 2005-05-02
Tsunamis and Earthquakes - 2005 Sri Lanka Tsunami Study - USGS WCMG USGS Western Coastal and Marine Geology was part of an international team that studied sediment deposits in Sri Lanka from the tsunami generated by the magnitude 9.0 Sumatra earthquake on December 26, 2004 Posted: 2005-02-14
Natural Disasters - Forecasting Hurricane Occurrence Events such as hurricanes, earthquakes, floods, tsunamis, volcanic eruptions, and tornadoes are natural disasters because they negatively impact society, and so they must be measured and understood in human-related terms. At the U.S. Geological Survey, we have developed a new method to examine fatality and dollar-loss data, and to make probabilistic estimates of the frequency and magnitude of future events. This information is vital to large sectors of society including disaster relief agencies and insurance companies. Posted: 2003-03-02
USGS OFR 03-13 - Cascadia Tsunami Deposit Database The Cascadia Tsunami Deposit Database contains data on the location and sedimentological properties of tsunami deposits found along the Cascadia margin. Data have been compiled from 52 studies, documenting 59 sites from northern California to Vancouver Island, British Columbia that contain known or potential tsunami deposits. Bibliographical references are provided for all sites included in the database. Cascadia tsunami deposits are usually seen as anomalous sand layers in coastal marsh or lake sediments. The studies cited in the database use numerous criteria based on sedimentary characteristics to distinguish tsunami deposits from sand layers deposited by other processes, such as river flooding and storm surges. Several studies cited in the database contain evidence for more than one tsunami at a site. Data categories include age, thickness, layering, grainsize, and other sedimentological characteristics of Cascadia tsunami deposits. The database documents the variability observed in tsunami deposits found along the Cascadia margin. Posted: 2003-01-01
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