Last night when be informed Alaska strong shock, United States to give out early-warning of seismic sea wave for a short while, I contacted the scientist of leading authority class of domain of a few earthquakes. Wait for calamity about the volcano that frequency sends recently, earthquake, you want to know was here.
Beijing time on January 23 17 when 31 minutes, 7.9 class earthquake happens in American Alaska bay, the magnitude that bureau of American geological exploration determines at first is 8 class, amend after for 8.2 class, it is 7.9 class finally surely. Focus deepness is 25 kilometers about.
After strong shock happening before long, center of early-warning of Pacific Ocean seismic sea wave namely to the United States the coast gives out early-warning of seismic sea wave on the west. Nevertheless, current, center of early-warning of Pacific Ocean seismic sea wave already cancelled early-warning of seismic sea wave.
Meanwhile, according to media coverage, same day, be located in Japan group the Bai Genshan of active volcano careless ferry of ministry of equestrian county northwest erupts, cause an avalanche; Indonesian area of Su Jiawu eyebrow produces Java on the west earthquake of 6.4 on the Richter scale, focus deepness is 10 kilometers, capital Jakarta has intense shake feeling. In addition, on January 21, chile north ever also produced 6.3 class earthquake.
Chen Yuntai (academician of the Chinese Academy of Sciences) : Preliminary conclude this earthquake slips to go model give priority to incident.
Research group of Chen Yuntai perform the burst course result that got this second earthquake instead for a short while. According to the result, duration of this earthquake burst is 60 seconds about, most Great Harmony shake the fault amounts to about 8 meters, burst edge moves toward Xiang Nana to exhibit about 80 kilometers to develop eastward, deviate from the trend extends about 120 kilometers to north-northwest direction, area of the main burst that be the same as shake is located in be in from focus inside the area range that northerly north extends about 40 kilometers on the west.
Zhang Peizhen (academician of the Chinese Academy of Sciences) : Belt of shake of country of matches of annulus peace and tranquility is really special and active.Belt of shake of country of matches of annulus peace and tranquility is very active all the time. Volcanic to annulus Pacific Ocean shake belt is at present active period time interval, the academia is done not have accurate and unified judgement, roughly time interval may come 50 years in 30 years.
Volcano of annulus Pacific Ocean is taken, call annulus Pacific Ocean belt of belt, earthquake of annulus Pacific Ocean or igneous annulus again, it is an area that often produces earthquake and volcano to erupt around Pacific Ocean, full-court 40 thousand kilometer, submit horse's hoof form. Annulus Pacific Ocean has a chain of trench, a chain of islands and volcano on volcanic belt, board piece mobile and acuteness. Volcano of annulus Pacific Ocean takes mutual active volcano 512, 80% what take measure of global active volcano. Be located in Asia-Europe board piece with Pacific Ocean board piece between, the lithosphere moves frequent.
Great majority earthquake happens on this earthquake belt, happened inside the time of close not curious. A kinetic process delivers so long distance, certain need compares long time. The trends of seismic wave sparks is the mechanism that can deliver quickly, but spark ability is limited.
If from long measure looks, the whole world is an old system, shake of earth of annulus Pacific Ocean can cause a lithosphere stress can happen migratory, spark easily other area produces volcano to erupt or seismic calamity.
2004 after Sumatra produces 9 class earthquake, the whole world activity of 8 class earthquake is relatively brisk, large area of amount of Qinghai-Tibet Platean earthquake increases, our country Qinghai-Tibet Platean produced strong shock of 6 class above 8 times after 2008, back-to-back move occurred jade to cultivate an earthquake 2010, produced earthquake of plain of short of Wenshui River 2013. Corresponding area still ought to do good calamity to be on guard the job.
Why does early-warning of seismic sea wave fail?In addition, there ever was large-scale strong shock 3 times on Alaska history, the 9.1 class that were 1957 respectively, the 8.4 class 1964 and the 8.7 class 1965. Around all causes large seismic sea wave twice.
After this 8 class earthquake happens, bureau of American country scene gives out early-warning of seismic sea wave and the appeal suffers the people that affects an area to lest be reached by disaster,take refugee toward altitude, coastal region of American Alaska, Washington city, California includes to be inside alarm limits.
Seismic sea wave gives out for a short while seismic expert points out rate of false alarm of early warning system of Pacific Ocean seismic sea wave is louder, the probability that Alaska bay earthquake causes massive seismic sea wave is not big. If really, did not pass how long did early-warning of seismic sea wave cancel.
So why can early-warning of seismic sea wave fail?
Traditional early-warning basically is to pass seismic data to perform focus parameter instead first, whether does judgement earthquake belong to earthquake of seismic sea wave, if be if release early-warning of seismic sea wave. Adopt the time difference between seismic wave and wave of seismic sea wave, this kind of early-warning can arrive in seismic sea wave before a few minutes in release, flee for his life to everybody time. Nevertheless, if the parameter such as focus mechanism or deepness forbids, the accuracy that meeting influence performs instead is brought about then sign up for by accident.
