Tag: tsunami

May lead to better early warning systems The tsunami that devastated Japan on March 11 was picked up by high-frequency radar in California and Japan as it swept toward their coasts, according to U.S. and Japanese scientists. This is the first time that a tsunami has been observed by radar, raising the possibility of new early warning systems."It could be really useful in areas such as south-east Asia where there are huge areas of shallow continental shelf," said Professor John Largier, an oceanographer at the University of California, Davis, Bodega Marine Laboratory, and an author of a new paper describing the work. The paper appears this month in the journal Remote Sensing.Largier and his colleagues have been using a high-frequency radar array at the Bodega Marine Lab to study ocean currents for the last 10 years. The Bodega lab is part of a network of coastal radar sites funded by the State of California for oceanographic research.Largier, together with collaborators from Hokkaido and Kyoto universities in Japan and San Francisco State University, used data from radar sites at Bodega Bay, Trinidad, Calif., and two sites in Hokkaido, Japan, to look for the tsunami offshore.The scientists found that the radar picks ...

It will be tested on 10 August The Tsunami Early Warning and Mitigation System in the North-eastern Atlantic, the Mediterranean and connected seas (NEAMTWS) will be tested on 10 August.The purpose of the test of the warning system, first established in 2005 under the aegis of UNESCO's Intergovernmental Oceanographic Commission (IOC), is to ensure effective communication between regional and national centres and tsunami warning focal points.Thirty-one countries will take part in the exercise which will include sending test messages via electronic mail, fax and the Global Telecommunication System (GTS) from the Istanbul Observatory and Earthquake Research Institute (KOERI, Turkey) to all the national centres and tsunami warning focal points in the region concerned. This should reveal possible dysfunctions in the dissemination of warnings. Indeed, the fast transmission of data and reactivity of national centres and country focal points are crucial for the effectiveness of the entire tsunami warning system.Historically strong seismic activity has been observed in the Mediterranean and North-eastern Atlantic, albeit less frequently than in the Pacific Ocean. A powerful earthquake in the Azores-Gibraltar Fault zone and subsequent tsunami destroyed the city of Lisbon in 1755. In 1908, a tsunami took the lives of 85,000 people in Messina (Italy). ...

Providing accurate and real-time data on tsunamis The NOAA took 20 years to develop a reliable tsunamograph, an apparatus that provides accurate, real-time data on tsunamis. It consists of an anchored, ocean-bottom pressure recorder and a companion buoy (called DART, for Deep-Ocean Assessment and Reporting of Tsunamis). The recorder, sitting at a depth of up to 5,000 meters, measures changes in pressure due to changes in water level.The recorder transmits acoustic signals to the buoy, which, in turn, relays the measurements of wave height to satellites. This information is then used to forecast the progress of a tsunami. Although each tsunamograph costs a mere $200,000, there are only about 50 in operation worldwide.There are scarcely any in the middle of the Pacific, and practically none in the Indian Ocean. Each dot on the map above represents a single buoy, an object about five feet wide that resembles a flying saucer. Many countries, such as India and Indonesia, have resisted acquiring DARTs from the NOAA out of a sense of "security nationalism."Japan relies on land-based cables that connect to ocean-floor recorders. This is less reliable than buoys, as cables tend to snap when the earthquake fault deforms the seafloor they lie ...

No immediate reports of injuries or damage A powerful earthquake struck off Japan's northeastern coast on Sunday. Tsunami advisories were issued following the Japan earthquake, Tokyo Breaking News reported. The alert was later lifted.According to Reuters, Fukushima nuclear plant workers evacuated to higher ground following the earthquake, with no immediate reports of injuries or damage. Tokyo Electric Power said that there did not appear to be any further damage at the nuclear plant.In March, Japan's earthquake and tsunami devastated the country, and wreaked havoc at the Fukushima nuclear plant.The Associated Press reports:The quake hit at 9:57 local time (0057 GMT), and a warning of a tsunami was issued for most of the northeastern coastline. The epicenter of the quake was in the Pacific Ocean off the coast of Japan's main island, Honshu, at a depth of about 20 miles (30 kilometers).Japanese officials predicted the quake could generate tsunami of up to 20 inches (50 centimeters), but the initial waves were only about 4 inches (10 centimeters).The tsunami warning was lifted after the forecast arrival time of the waves passed in most areas without any tsunami being recorded.Japan's Meteorological agency at first estimated the strength of the quake at 7.1, but ...