Stebo Posted September 2, 2011 Share Posted September 2, 2011 Breaking news: 7.1 quake strikes near Alaska; Tsunami warning Occurred about 1/2 hour ago. Tsunami Warning info TSUNAMI MESSAGE NUMBER 1NWS WEST COAST/ALASKA TSUNAMI WARNING CENTER PALMER AK 259 AM AKDT FRI SEP 2 2011 ...A TSUNAMI WARNING IS NOW IN EFFECT WHICH INCLUDES THE COASTAL AREAS OF ALASKA FROM UNIMAK PASS ALASKA/80 MILES NE OF DUTCH HARBOR/ TO AMCHITKA PASS ALASKA/125 MILES W OF ADAK/... ...THIS MESSAGE IS INFORMATION ONLY FOR COASTAL AREAS OF CALIFORNIA - OREGON - WASHINGTON - BRITISH COLUMBIA AND ALASKA FROM THE CALIFORNIA-MEXICO BORDER TO UNIMAK PASS ALASKA/80 MILES NE OF DUTCH HARBOR/... ...THIS MESSAGE IS INFORMATION ONLY FOR COASTAL AREAS OF ALASKA FROM AMCHITKA PASS ALASKA/125 MILES W OF ADAK/ TO ATTU ALASKA... RECOMMENDED ACTIONS PERSONS IN LOW-LYING COASTAL AREAS SHOULD BE ALERT TO INSTRUCTIONS FROM THEIR LOCAL EMERGENCY OFFICIALS. EVACUATIONS ARE ONLY ORDERED BY EMERGENCY RESPONSE AGENCIES. - PERSONS IN TSUNAMI WARNING COASTAL AREAS SHOULD MOVE INLAND TO HIGHER GROUND. PRELIMINARY EARTHQUAKE PARAMETERS MAGNITUDE - 7.1 TIME - 0256 AKDT SEP 02 2011 0356 PDT SEP 02 2011 1056 UTC SEP 02 2011 LOCATION - 51.8 NORTH 171.4 WEST 45 MILES/72 KM SE OF AMUKTA PASS ALASKA 230 MILES/370 KM E OF ADAK ALASKA DEPTH - 24 MILES/39 KM TSUNAMI WARNINGS MEAN THAT A TSUNAMI WITH SIGNIFICANT WIDESPREAD INUNDATION IS IMMINENT... EXPECTED OR OCURRING. WARNINGS INDICATE THAT WIDESPREAD DANGEROUS COASTAL FLOODING ACCOMPANIED BY POWERFUL CURRENTS IS POSSIBLE AND MAY CONTINUE FOR SEVERAL HOURS AFTER THE INITIAL WAVE ARRIVAL. PACIFIC COASTAL REGIONS OUTSIDE CALIFORNIA/ OREGON/ WASHINGTON/ BRITISH COLUMBIA AND ALASKA SHOULD REFER TO THE PACIFIC TSUNAMI WARNING CENTER MESSAGES FOR INFORMATION ON THIS EVENT AT WWW.WEATHER.GOV/PTWC. THIS MESSAGE IS BASED MAINLY ON EARTHQUAKE DATA. EARTHQUAKES OF THIS SIZE ARE KNOWN TO GENERATE DANGEROUS TSUNAMIS. AS MORE INFORMATION BECOMES AVAILABLE THE WARNING AREAS WILL BE REFINED. THIS MESSAGE WILL BE UPDATED IN 30 MINUTES OR SOONER IF THE SITUATION WARRANTS. THE TSUNAMI MESSAGE WILL REMAIN IN EFFECT UNTIL FURTHER NOTICE. REFER TO THE INTERNET SITE WCATWC.ARH.NOAA.GOV FOR MORE INFORMATION. AKZ185-187-021159- /O.NEW.PAAQ.TS.W.0021.110902T1059Z-000000T0000Z/ COASTAL AREAS BETWEEN AND INCLUDING UNIMAK PASS ALASKA/80 MILES NE OF DUTCH HARBOR/ TO AMCHITKA PASS ALASKA/125 MILES W OF ADAK/ 259 AM AKDT FRI SEP 2 2011 ...A TSUNAMI WARNING IS NOW IN EFFECT WHICH INCLUDES THE COASTAL AREAS OF ALASKA FROM UNIMAK PASS ALASKA/80 MILES NE OF DUTCH HARBOR/ TO AMCHITKA PASS ALASKA/125 MILES W OF ADAK/... PERSONS IN TSUNAMI WARNING COASTAL AREAS SHOULD MOVE INLAND TO HIGHER GROUND. TSUNAMI WARNINGS MEAN THAT A TSUNAMI WITH SIGNIFICANT WIDESPREAD INUNDATION IS IMMINENT... EXPECTED OR OCCURRING. TSUNAMIS ARE A SERIES OF WAVES POTENTIALLY DANGEROUS SEVERAL HOURS AFTER INITIAL ARRIVAL TIME. ESTIMATED TIMES OF INITIAL WAVE ARRIVAL FOR SELECTED SITES IN THE WARNING ARE PROVIDED BELOW. ADAK-AK 0352 AKDT SEP 2 DUTCH HARBOR-AK 0412 AKDT SEP 2 FOR ARRIVAL TIMES AT ADDITIONAL LOCATIONS SEE WCATWC.ARH.NOAA.GOV Link to comment Share on other sites More sharing options...
Chambana Posted September 2, 2011 Share Posted September 2, 2011 http://news.yahoo.com/7-1-magnitude-quake-strikes-off-alaska-usgs-113023925.html Link to comment Share on other sites More sharing options...
Chambana Posted September 2, 2011 Share Posted September 2, 2011 Just posted a thread on this topic, you beat me to it mods please delete mine. how often do earthquakes strike alaska? not very often i'm assuming? Link to comment Share on other sites More sharing options...
NaoPos Posted September 2, 2011 Share Posted September 2, 2011 Just posted a thread on this topic, you beat me to it mods please delete mine. how often do earthquakes strike alaska? not very often i'm assuming? more often than you would think. from this article:http://seismic.alaska.gov/seismic_hazards_earthquake_risk.htm ALASKA EARTHQUAKE STATISTICS Alaska is home of the the second largest earthquake ever recorded (1964 Great Alaska Earthquake, magnitude 9.2) Alaska has 11 percent of the world�s recorded earthquakes Three of the eight largest earthquakes in the world were in Alaska Seven of the ten largest earthquakes in the United States were in Alaska Since 1900, Alaska has had an average of: One �great� earthquake (magnitude 8 or larger) earthquake every 13 years One magnitude 7 to 8 earthquake every year Six magnitude 6 to 7 earthquakes per year Forty five magnitude 5 to 6 earthquakes per year Three hundred twenty magnitude 4 to 5 earthquakes per year An average of a 1,000 earthquakes are located in Alaska each month Link to comment Share on other sites More sharing options...
mappy Posted September 2, 2011 Share Posted September 2, 2011 Just posted a thread on this topic, you beat me to it mods please delete mine.how often do earthquakes strike alaska? not very often i'm assuming? I'm going to assume, you meant how many "larger" earthquakes strike alaska, because earthquakes happen there all the time http://earthquake.usgs.gov/earthquakes/recenteqsus/Maps/special/Alaska.php Link to comment Share on other sites More sharing options...
Scorpion Posted September 2, 2011 Share Posted September 2, 2011 The tsunami will be completely insignificant. Don't know why they bother with that warning for only a 7.1 Link to comment Share on other sites More sharing options...
Srain Posted September 2, 2011 Share Posted September 2, 2011 BULLETINTSUNAMI MESSAGE NUMBER 3 NWS WEST COAST/ALASKA TSUNAMI WARNING CENTER PALMER AK 357 AM AKDT FRI SEP 2 2011 ...THE TSUNAMI WARNING IS CANCELED FOR THE COASTAL AREAS OF ALASKA FROM UNIMAK PASS ALASKA/80 MILES NE OF DUTCH HARBOR/ TO AMCHITKA PASS ALASKA/125 MILES W OF ADAK/... EVALUATION NO DESTRUCTIVE TSUNAMI HAS BEEN RECORDED. NO TSUNAMI DANGER EXISTS FOR ALASKA/ BRITISH COLUMBIA/ WASHINGTON/ OREGON OR CALIFORNIA. LOCAL AUTHORITIES CAN ASSUME ALL CLEAR UPON RECEIPT OF THIS MESSAGE. PRELIMINARY EARTHQUAKE PARAMETERS MAGNITUDE - 7.1 TIME - 0256 AKDT SEP 02 2011 0356 PDT SEP 02 2011 1056 UTC SEP 02 2011 LOCATION - 51.8 NORTH 171.4 WEST 45 MILES/72 KM SE OF AMUKTA PASS ALASKA 225 MILES/362 KM E OF ADAK ALASKA DEPTH - 24 MILES/39 KM PACIFIC COASTAL REGIONS OUTSIDE CALIFORNIA/ OREGON/ WASHINGTON/ BRITISH COLUMBIA AND ALASKA SHOULD REFER TO THE PACIFIC TSUNAMI WARNING CENTER MESSAGES FOR INFORMATION ON THIS EVENT AT WWW.WEATHER.GOV/PTWC. THIS WILL BE THE LAST WEST COAST/ALASKA TSUNAMI WARNING CENTER MESSAGE ISSUED FOR THIS EVENT. THIS INFORMATION IS ALSO POSTED AT WCATWC.ARH.NOAA.GOV. AKZ185-187-021357- /O.CAN.PAAQ.TS.W.0021.000000T0000Z-000000T0000Z/ COASTAL AREAS BETWEEN AND INCLUDING UNIMAK PASS ALASKA/80 MILES NE OF DUTCH HARBOR/ TO AMCHITKA PASS ALASKA/125 MILES W OF ADAK/ 357 AM AKDT FRI SEP 2 2011 ...THE TSUNAMI WARNING IS CANCELED FOR THE COASTAL AREAS OF ALASKA FROM UNIMAK PASS ALASKA/80 MILES NE OF DUTCH HARBOR/ TO AMCHITKA PASS ALASKA/125 MILES W OF ADAK/... $$ Link to comment Share on other sites More sharing options...
NaoPos Posted September 2, 2011 Share Posted September 2, 2011 The tsunami will be completely insignificant. Don't know why they bother with that warning for only a 7.1 Sorry, not every tsunami is going to be 20-30 Meters high.... Even a 1 meter tsunami can do some damage to immediate coastal areas. Link to comment Share on other sites More sharing options...
RodneyS Posted September 2, 2011 Share Posted September 2, 2011 Sorry, not every tsunami is going to be 20-30 Meters high.... Even a 1 meter tsunami can do some damage to immediate coastal areas. I believe that a 7.1 magnitude earthquake can generate a tsunami only under very unusual circumstances. My understanding is that an earthquake generally has to be at least a 7.5 magnitude for that to happen. Does anyone know what the smallest magnitude earthquake to generate a tsunami was? Link to comment Share on other sites More sharing options...
k*** Posted September 2, 2011 Share Posted September 2, 2011 I believe that a 7.1 magnitude earthquake can generate a tsunami only under very unusual circumstances. My understanding is that an earthquake generally has to be at least a 7.5 magnitude for that to happen. Does anyone know what the smallest magnitude earthquake to generate a tsunami was? It's a complicated question. I know for a fact that smaller earthquakes have caused significant tsunamis...for instance, a 1998 earthquake in Papua New Guinea caused a significant tsunami that killed thousands and it was barely a 7. Link to comment Share on other sites More sharing options...
joe1946 Posted September 2, 2011 Share Posted September 2, 2011 USGS : 6.8 http://earthquake.usgs.gov/earthquakes/recenteqsus/Quakes/quakes_big.php Link to comment Share on other sites More sharing options...
Mallow Posted September 2, 2011 Share Posted September 2, 2011 Just posted a thread on this topic, you beat me to it mods please delete mine. how often do earthquakes strike alaska? not very often i'm assuming? You've got to be kidding. Alaska is probably the most seismically active state in the nation. Link to comment Share on other sites More sharing options...
RodneyS Posted September 2, 2011 Share Posted September 2, 2011 It's a complicated question. I know for a fact that smaller earthquakes have caused significant tsunamis...for instance, a 1998 earthquake in Papua New Guinea caused a significant tsunami that killed thousands and it was barely a 7. Thanks, that's very interesting. According to http://en.wikipedia.org/wiki/1998_Papua_New_Guinea_earthquake The 1998 Papua New Guinea earthquake was a magnitude 7.0 earthquake that took place in the early evening of Friday, 17 July 1998. The earthquake struck the north coast region of Papua New Guinea, 25 km (16 mi) from the coast near Aitape, and caused a large undersea landslide, which in turn caused a tsunami that hit the coast, killing more than 2200 people . . . The cause of the tsunami from the landslide has changed perceptions from scientists about small earthquakes generating undersea landslides, and made them realise that undersea landslides are more of a hazard, as they cause 'surprise' tsunamis, as there is less warning of an undersea landslide than an undersea earthquake, which is normally felt by people on land, and detected by the Pacific Tsunami Warning Center. This has made them re-evaluate the tsunami risk around the world. Link to comment Share on other sites More sharing options...
Drz1111 Posted September 2, 2011 Share Posted September 2, 2011 There are two different kinds of tsunamis. One, generated by landslide/slumps/turbidite flows, can be connected to moderate earthquakes (text book example: Labrador/Newfoundland, 1929). These tsunamis can be very severe in the immediate area of the landslide, but decay rapidly with distance. Basin-crossing tsunamis are formed by the movement of large areas of the the crust under the ocean in response to the stress release of the earthquake (as opposed to the "local" tsunamis, which are generated by local movement of sediment). These are only generated by very large earthquakes which move a sufficiently large area of crust to displace a large volume of water. HTFH. Link to comment Share on other sites More sharing options...
RodneyS Posted September 2, 2011 Share Posted September 2, 2011 There are two different kinds of tsunamis. One, generated by landslide/slumps/turbidite flows, can be connected to moderate earthquakes (text book example: Labrador/Newfoundland, 1929). These tsunamis can be very severe in the immediate area of the landslide, but decay rapidly with distance. Basin-crossing tsunamis are formed by the movement of large areas of the the crust under the ocean in response to the stress release of the earthquake (as opposed to the "local" tsunamis, which are generated by local movement of sediment). These are only generated by very large earthquakes which move a sufficiently large area of crust to displace a large volume of water. HTFH. Thanks, this explains why tsunami warnings are issued for less than major (7.0 magnitude) earthquakes -- it's not the basin-crossing tsunami that's the concern; rather, it's the landslide that may be caused by the earthquake, which in turn may generate a tsunami. Link to comment Share on other sites More sharing options...
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