For all of the devastation caused by the 2011 earthquake/tsunami in Japan, the former, a 9.0 magnitude
Until 2003, when Japanese seismologist Hiroo Kanamori and UC Berkeley?s Richard Allen published a study proving that early detection was possible, warning systems for earthquakes have relied on a concept that?s been around since the 19th century: detect the ground shaking at the fault line and send advanced notice to cities miles away through telegraphs, telephones, or modern telecommunications (depending on which century you?re in).
This system relies on the fact that electronic signals move much faster than seismic waves; For example, if you were in New York and on Twitter on August 23, 2011, you might have seen tweets from Washington DC about their earthquake
The new system put into place in Japan in 2007 detects earthquakes before they start shaking the Earth?s surface. Allen and Kanamori found that when tectonic plates shift, they release two forms of energy simultaneously, called p-waves and s-waves. S-waves cause all the damage on the surface. P-waves are harmless, but travel through the ground about twice as fast. So when Japan?s more than 1,000 seismometers near their Pacific fault-line relayed p-wave data indicating a massive earthquake, the Japanese Meteorological Agency rang the alarm.
While this ?early detection? still only gives about 60 seconds of warning, Japan was able to safely stop eleven 320-km/h bullet trains, disable 16,000 elevators, warn students to get under their desks, and set off earthquake alarms across the country. Some 52 million Japanese received text alerts on their cellphones. But that?s because Japan has the advanced warning system and a cultural awareness of the threat of earthquakes (for example, new iPhones bought in Japan come with quake-warning features built in).
California, on the other hand? Azeen Ghorayshi, in a great feature for the East Bay Express about Japan and California?s preparedness, says that California still has ?next to nothing in terms of a public seismic warning system,? despite knowing how to build one for almost a decade and despite knowing the next ?big one? is only matter of time. But building a statewide system is only a matter of politics and money, so it?ll probably be ready in no time. Meanwhile, here?s a $1 iPhone Seismometer app
Source: http://gizmodo.com/the-california-made-earthquake-alarm-that-works-but-cal-486349057
Hunter Hayes rick warren Final Four 2013 final four Ray J I Hit It First Rick Pitino Spike Albrecht
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.