{"72030":{"#nid":"72030","#data":{"type":"news","title":"Scientists Report Java Tsunami Gave No Warning","body":[{"value":"\u003Cp\u003EThough categorized as magnitude 7.8, the earthquake could scarcely be felt by beachgoers that afternoon.  A low tide and wind-driven waves disguised the signs of receding water, so when the tsunami struck, it caught even lifeguards by surprise.  That contributed to the death toll of more than 600 persons in Java, Indonesia.\u003C\/p\u003E\n\u003Cp\u003E\u0022The general assumption was that if you were near the coast where the earthquake took place, you would feel it and be able to run to higher ground,\u0022 said Hermann Fritz, first author of a new \u003Cem\u003EGeophysical Research Letters \u003C\/em\u003Epaper about the July 17, 2006 tsunami.  \u0022This event caught people by surprise and showed that it\u0027s not always that simple.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe earthquake was slow rupturing, so it didn\u0027t produce strong ground shaking on Java that might have alerted people on the beach, he explained.\n\u003C\/p\u003E\n\u003Cp\u003ENo local warning was issued for the tsunami waves, which arrived only tens of minutes after the earthquake.  Fortunately, the event took place on a Monday.  Had the massive waves hit the day before, which was a major national holiday, the popular beach would have been much more crowded - and the toll higher.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Warning systems typically don\u0027t work very well for locations near earthquakes, where there are only tens of minutes between the earthquake and the tsunami\u0027s arrival,\u0022 noted Fritz, a Georgia Institute of Technology assistant professor who led an inspection team to Java a week after the event.  \u0022It\u0027s pretty much a spontaneous self-evacuation.  You normally feel the earthquake or see the ocean withdraw. If you hear the noise in the last tens of seconds before it hits, then it\u0027s just a matter of who makes it and who doesn\u0027t.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe survey team, which included scientists from five different countries, interviewed survivors and studied evidence left behind by the tsunami, including debris fields.  Beyond the quiet nature of the catastrophe, they discovered evidence of a 21-meter (65-foot) wave that hit a portion of the coastline near the island of Nusa Kambangan, indicating a second event that may have added to the severity of the disaster.\n\u003C\/p\u003E\n\u003Cp\u003EElsewhere along the 300 kilometers of coastline studied by the International Tsunami Survey team, the waves ranged from 5 to 7 meters, 16 to 24 feet.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022This event indicates that there was likely a combination of both a tectonic tsunami and a submarine landslide or a canyon failure triggered by the earthquake,\u0022 said Fritz, whose research is supported by the U.S. National Science Foundation. \u0022The runup was unusually high along one portion of the coast, too much for a 7.8 magnitude earthquake.  The only explanation we could think of is that a submarine mass movement triggered by the earthquake could have added to the effect of the earthquake, given the essentially straight coastline with little room for large-scale tsunami focusing.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EFor people in seismically-active areas like Indonesia, an earthquake usually provides the first warning of a tsunami.  Whether caused by an earthquake or an underwater landslide, the first visible sign of an oncoming tsunami is often a rapid withdrawal of the ocean that exposes the seafloor or coral reefs.  When that appears, the first tsunami wave won\u0027t be far behind.\n\u003C\/p\u003E\n\u003Cp\u003EIn the July 2006 Java tsunami, lifeguards did not notice the withdrawal because the water was receding anyway because of a normal low tide - and because of large wind-produced waves.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022The lifeguards did not recognize the precursors of the tsunami, either the shaking of the earth or the drawing down of the sea,\u0022 said Fritz, who also interviewed survivors of the 2004 Indonesian tsunami.  \u0022The irony is that many of the lifeguards survived because they were in tall concrete structures sitting more than four meters above the ground, getting just their feet wet - a classic example of vertical evacuation in engineered structures.  We interviewed one of them, and it was quite moving.  It was his job to watch out for the people on the beach, and what happened was pretty tough on him.\u0022\n\u003C\/p\u003E\n\u003Cp\u003ESurvivors compared the sound of the tsunami to that of an aircraft landing or a loud boiling sound.  \u0022That primarily comes from the bore forming, or breaking of the waves a couple of hundred meters off shore,\u0022 Fritz explained.  \u0022In high impact areas, the first tsunami wave then comes in as a rolling wave of water, whereas in low-impact areas it may only be recognized as an unusually fast and high tide.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EA tsunami normally produces more than one wave, and the waves can be 10 or 20 minutes apart.  Often, the second or third wave is the largest, so many deaths occur when victims return to low-lying areas to look for relatives or assess damage after the first wave hits.\n\u003C\/p\u003E\n\u003Cp\u003EIn Indonesia, the government has instituted education programs to help residents respond to tsunami warning signs by quickly moving to higher ground.  In many cases, safety can mean moving a mile inland or 10 meters up a hill.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022It\u0027s always going to be difficult to provide a warning in Java because the earthquake zone is so near,\u0022 explained Fritz, a faculty member at Georgia Tech\u0027s Savannah, Ga. campus.  \u0022It\u0027s most critical for people to be able to evacuate themselves.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EIn other locations, such as the Hawaiian Islands, warning systems are useful because tsunamis caused by continental earthquakes take hours to reach the islands, he said.\n\u003C\/p\u003E\n\u003Cp\u003EIn the deep ocean, tsunami waves move at the speed of a jet aircraft.  However, when they approach land, the waves slow as their height builds and energy dissipates.  By the time they roll onto a beach, the waves may be moving at vehicle highway speed, but that quickly drops as they encounter structures and vegetation.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022If you start running from the beach when the tsunami strikes, chances are you are not going to make it,\u0022 Fritz said. \u0022But if you have a head-start, you have a much better chance - if you know where you\u0027re going.\u0022\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 100\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Contact\u003C\/strong\u003E: John Toon (404-894-6986); E-mail: (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ETechnical Contact\u003C\/strong\u003E: Hermann Fritz (912-966-7947); E-mail (\u003Ca href=\u0022mailto:hermann.fritz@gtsav.gatech.edu\u0022\u003Ehermann.fritz@gtsav.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Waves reached-65 feet in disaster last summer"}],"field_summary":[{"value":"Though categorized as magnitude 7.8, the earthquake could scarcely be felt by beachgoers that afternoon.  A low tide and wind-driven waves disguised the signs of receding water, so when the tsunami struck, it caught even lifeguards by surprise -- contributing to the death toll.","format":"limited_html"}],"field_summary_sentence":[{"value":"Study shows lack of warning in Java disaster"}],"uid":"27303","created_gmt":"2007-06-19 00:00:00","changed_gmt":"2016-10-08 03:03:29","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2007-06-19T00:00:00-04:00","iso_date":"2007-06-19T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"72031":{"id":"72031","type":"image","title":"Coastal tsunami damage","body":null,"created":"1449177425","gmt_created":"2015-12-03 21:17:05","changed":"1475894649","gmt_changed":"2016-10-08 02:44:09"},"72032":{"id":"72032","type":"image","title":"Interviewing a survivor","body":null,"created":"1449177425","gmt_created":"2015-12-03 21:17:05","changed":"1475894649","gmt_changed":"2016-10-08 02:44:09"},"72033":{"id":"72033","type":"image","title":"Height distribution of waves","body":null,"created":"1449177425","gmt_created":"2015-12-03 21:17:05","changed":"1475894649","gmt_changed":"2016-10-08 02:44:09"}},"media_ids":["72031","72032","72033"],"related_links":[{"url":"http:\/\/www.gtsav.gatech.edu\/go\/faculty\/hermann-fritz-ph-d","title":"Hermann Fritz"},{"url":"http:\/\/www.gtsav.gatech.edu\/","title":"Georgia Tech Savannah"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"154","name":"Environment"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"5770","name":"Earthquake"},{"id":"7559","name":"Java"},{"id":"347","name":"tsunami"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}