Sunday, September 24, 2006
Canary Island Tsunami Threat
Since the Indonesian Tsunami of 2004, there has been a lot of discussion about a potential Atlantic Basin wide tsunami triggered by a landslide on the volcanic island of La Palma in the Canary Islands. 
Image copyright Geology.com and Map ResourcesStudies of surface faulting produced by a 1949 eruption suggest that a large mass of between 200 and 500 cubic kilometers could slip into the sea, generating an Atlantic Ocean tsunami with basin-wide impact. Models suggest that these waves could be 100 meters high at adjacent islands, 50-100 meters high on the African coast, 7-10 meters high at Spain and the UK and over 20 meters high on the coast of Florida.
From: Atlantic Ocean Tsunami Threat, September, 2005 More recent studies by researchers at Delft University of Technology suggest that the risk is much lower than previously thought. Required for a near future failure would be a situation of exceptionally heavy rainfall accompanied by a strong magmatic outburst. The risk would increase with time, however, as the Cumbre Vieja volcano grows and the flanks become less stable. Read more about Canary Island Tsunami Threat. Labels: Tsunamis
Wednesday, July 26, 2006
United States Tsunami Hazard Summary by USGS
The United States Geological Survey has published a fact sheet that details tsunami hazards to the United States. Tsunamis can be triggered by earthquakes, volcanic eruptions, submarine landslides and onshore landslides in which a large volume of material slips into the water - all of these can produce tsunami events that could impact the United States. Their fact sheet includes a map showing shoreline areas that have been impacted by past tsunami events triggered by large earthquakes. These include the Prince William Sound, Alaska (9.2M, 1964); Chile (9.5M 1960); Alaska (7.3M, 1946); Puerto Rico/Mona Rift (7.4M, 1918); Virgin Islands (undetermined magnitude, 1967); Cascadia (9M, 1700); Puget Sound (7.5M, 900). 
Image by USGSFor more information see USGS Fact Sheet 2006-3023. Labels: Coastal-Geology, Tsunamis
Wednesday, July 19, 2006
Indonesia Tsunami Death Toll Tops 500
The death toll from Monday's tsunami that struck the Indonesian island of Java has topped 500 people. A Geotimes Extra article has been published, and questions about why a better tsunami warning was not broadcast. Labels: Tsunamis
Monday, July 17, 2006
7.7 Earthquake Causes 2 Meter Tsunami on Java
Image by USGS
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A major earthquake (magnitude 7.7) south of Java Island, Indonesia triggered a tsunami that has struck the southern shore of Java Island. The wave was approximately two meters high on the Pangandaran shoreline area of Java. At least 50 people have been killed and hundreds missing and injured. This earthquake is a result of thrust-faulting on the boundary between the Australia and Sunda Plates. Here the Australia Plate is moving north-northeast at about 6 centimeters per year relative to the Sunda Plate. It underthrusts the Sunda Plate at the Java Trench. 
Image Copyright by Geology.com and Map Resources.Read more about what causes a tsunami?. Labels: Earthquakes, Tsunamis
Monday, January 02, 2006
Tsunami: Wave that Shook the World
NOVA's "Wave that Shook the World" website has some very good information about tsunamis. Especially recommended is the "Anatomy of a Tsunami" and "Once and Future Tsunamis" interactives. A teacher's guide, program transcript and more are available at the website. 
NOVA ScreenshotVisit the website... Tsunami: Wave That Shook the World. Labels: Tsunamis
Thursday, December 29, 2005
California Tsunami
The State of California Seismic Safety Commission has released a report titled "The Tsunami Threat to California". This report includes a summary of the tsunami threat, findings related to the tsunami hazards of California and a list of recommended actions. Here is an excerpt of the tsunami situation from the report. "Damaging tsunamis are rare but potentially catastrophic events that present a danger to the people and economy of California. Over 80 tsunamis have been observed or recorded along the coast of California in the past 150 years, 9 causing minor damage in ports and harbors and 2 with major impacts. Four events caused deaths; the worst occurred in 1964 when 12 people died in California from the tsunami generated by the Great Alaska earthquake. Local earthquakes can produce damaging tsunamis that will provide very little warning time... 
Report cover from CSSCRead the entire California Tsunami Report (PDF document). Labels: Tsunamis
Friday, November 25, 2005
East Coast Tsunami Hazard Maps
Stephan Grilli and Christopher Baxter of the University of Rhode Island will study historical events and evaluate the risks and probabilities of a tsunami striking anywhere on the East Coast from the Carolinas to Maine. The researchers have received an $86,000 grant from FM Global, one of the world’s largest commercial property insurers, to create maps of the East Coast of the U.S. that will identify potential flooding and damage that could occur if a tsunami struck the region. Read more about East Coast Tsunami Hazard Maps at the University of Rhode Island website. Labels: Coastal-Geology, Tsunamis
Thursday, November 10, 2005
United States Tsunami Risk
David Pacchioli of Penn State has written an interview-style article with extensive quotes by Kevin Furlong, Penn State Geophysicist and tsunami expert. The article is titled: "Probing Question: Could a large tsunami ever hit the United States?". In this article he summarizes the various threats, including: undersea landslides off the California Coast, volcanic landslides in the Canary Islands and earthquake-generated tsunamis along the Cascadia Subduction Zone - just off shore of Oregon, Washington and British Columbia. Furlong says that the United States faces a "Big Time" tsunami threat. 
Image by California Department of TransportationRead more about the United States Tsunami Risk at Live.PSU.edu. Labels: Tsunamis
Saturday, November 05, 2005
Tsunami Heroine Honored
On December 26, 2004, Tilly Smith was 10 years old and on vacation with her parents in Thailand. While walking on the beach she noticed changes in the water levels that reminded her of a lesson on tsunamis in her geography class in Oxshott, England. She quickly told her parents and they ran toward their hotel. On the way she dashed toward a beach filled with bathers and warned them of the approaching wave. The beach was evacuated and an estimated 100 people avoided being caught in the wave. On Thursday, Tilly was honored at the United Nations in New York. Read more about the Tsunami Heroine at suntimes.com. Labels: Tsunamis
Saturday, October 29, 2005
Coastal Mangrove Forests Provide Tsunami Protection
Selvam Vaithilingam, Faizal Parish and others have published an article in "Science" which demonstrates how coastal mangrove forests provided significant protection to some shoreline areas during the December 2004 tsunami. Their conculsions are based upon the study of satellite images and ground surveys in the Cuddalore District of southeastern India. It also supports previous laboratory experiments suggesting that 30 trees per 100 square meters may reduce the maximum flow of a tsunami by more than 90 percent. 
Image by USGSRead more about mangrove tsunami protection at USNewsWire.com. Labels: Coastal-Geology, Tsunamis
Monday, September 26, 2005
Atlantic Ocean Tsunami Threat
Researchers at Benfield Hazard Research Center have identified a potential Atlantic Ocean tsunami threat from large-scale landslides at the Canary Islands. Surface and submarine investigations show a long-term history of mega-landslides at multiple locations in the Canary Island chain. Much of the current research focuses on the Cumbre Vieja volcano on the Canary Island of La Palma shown in the satellite image below. 
Image created from NASA Landsat Geocover 2000 dataStudies of surface faulting produced by a 1949 eruption suggest that a large mass of between 200 and 500 cubic kilometers could slip into the sea, generating an Atlantic Ocean tsunami with basin-wide impact. Models suggest that these waves could be 100 meters high at adjacent islands, 50-100 meters high on the African coast, 7-10 meters high at Spain and the UK and over 20 meters high on the coast of Florida. Although the probability of such a slide is very low, the enormous impact merits serious attention. 
Map by Geology.comRead more about the potential Atlantic Ocean Tsunami at the Benfield Hazard Research Center website. Another comprehensive article about Tsunami in the Atlantic Ocean can be seen that the Maine Geological Survey Website. Labels: Tsunamis
Friday, August 26, 2005
Tsunameter - Tsunami Detection & Warning System
Tsunameters are devices installed in the ocean to detect and measure the waves of a tsunami. Visit NOAA's Tsunami Homepage to learn about tsunameters, explore tsunami databases, see tsunami animations and learn all about these large and destructive waves. 
Image by NOAAVisit the NOAA Tsunami Website.... Tsunami Resources at Geology.com: What Causes a Tsunami?, Tsunami MapsLabels: Tsunamis
Thursday, July 14, 2005
Tsunami Earthquake Animation
Researchers at Delft University of Technology have created an animation that visually displays several elements of motion for the December 26, 2004 Earthquake. This earthquake occurred over a ten minute time interval. The animation shows the following.... 1) the progression of fault rupture across several hundred kilometers of seafloor, 2) propagation of the seismic surface waves, and 3) displacement of a few dozen GPS monitoring stations show large scale plate motions over the ten minute duration of the earthquake. This animation is worth watching and will make you realize that earthquake motion is not confined to a single point at the focus. View the Tsunami Earthquake Animation and more interesting graphics at the Delft University of Technology website. Available on geology.com are two articles: What Causes a Tsunami? and Indonesia Tsunami Maps. Labels: Earthquakes, Tsunamis
Sunday, July 03, 2005
Indian Ocean Tsunami Warning System Established
UNESCO announced the establishment of a tsunami warning system for the Indian Ocean. This is a multi-country cooperation to share expertise, data, equipment and communications to reduce the tsunami threat in the Indian Ocean. Work on the system has already begun and it is expected to be fully operational by July 2006. It will consist of enhanced seismograph networks, networks of real-time sea-level gauges and deep-sea ocean pressure sensors, along with national tsunami warning centers linked to national disaster management systems. Also announced were similar programs started for the Caribbean, the North-East Atlantic and the Mediterranean. Read more at the UNESCO Tsunami Website. Also posted at the UNESCO site are summaries of what individual countries have done to reduce the impact of tsunamis, including Australia, Indonesia, India, Iran, Japan, Korea, Kenya, Mauritius, Thailand, South Africa, Norway, Italy, Canada, United States, Germany, France, and Belgium. For more information about tsunamis visit our What Causes a Tsunami? and Tsunami Maps pages. Labels: Tsunamis
Wednesday, June 22, 2005
Tsunami Evacuation Maps
The Association of Bay Area Governments has an online GIS that serves a variety of different hazard maps. The most timely are tsunami evacuation maps for San Francisco and adjacent areas of California. Shakemaps, liquifaction maps, flooding maps, landslide maps and wildfire maps can also be produced on their website. Visit the ABAG site to view their " Tsunami Evacuation Maps".  Available on geology.com are two articles: What Causes a Tsunami? and Indonesia Tsunami Maps. Labels: Tsunamis
Saturday, June 18, 2005
Recent California Earthquakes Provide Tsunami Drill
Two recent articles in online editions of Seattle newspapers point out how the recent earthquakes that occurred off the California coast may have triggered some rethinking of current monitoring and emergency response procedures. One article is in the Seattle Times and the second in seattlepi.com. The June 14th 7.0 magnitude earthquake did not produce a dangerous tsunami because it had the wrong type of motion. It was produced by strike-slip motion instead of the vertical motion which displaces large amounts of seawater. See our article: " What Causes a Tsunami" for an illustrated explanation of the motion typically associated with a damaging tsunami. Labels: Tsunamis
Tuesday, May 31, 2005
Tsunami Warning Center Opens in Bangkok, Thailand
A new center for data monitoring and communications opened in Bangkok, Thailand on Monday. This center will receive data from existing tsunami monitoring networks and have the ability to broadcast warnings to Thai emergency response groups. Experts believe that this center will have the capability to save many lives if a repeat of the December 2004 tsunami occurs. The International Herald Tribune website has the best explanation of the Tsunami Warning Center in Thailand that we have seen so far. Available on geology.com are two articles: What Causes a Tsunami? and Indonesia Tsunami Maps. Labels: Tsunamis
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