California/Nevada in the past week alone. Now granted most of these were level 1 and 2, with an occasional 3 tossed in for good measure. My question is...were they all really EQs? how sensative are the monitors--would they give a false read for say, a building demolition? Please don't flame me. I went to the local science museum last week and they had a really interesting display-- enough to catch my interest and do some web surfing...
http://earthquake.usgs.gov/eqcenter/recenteqsus/Maps/US10/32.42.-125.-115.php
2007-01-02 11:18:05 · 4 answers · asked by wholenote4 4 in Science & Mathematics ➔ Earth Sciences & Geology
You've asked a totally reasonable question and Nature Nate is correct that seismographs can pick up explosions and the like. But seismologists have asked themselves the same question and developed methods for distinguishing large explosions from small earthquakes.If you click on the earthquake localities on map at the USGS url that you give--you will notice that you get information on the depth of the starting point of the earthquake. Click around and you'll see that the huge majority (all?) are several kilometers (miles) below the surface--so they're natural, not manmade.
2007-01-02 15:49:20 · answer #1 · answered by luka d 5 · 2⤊ 0⤋
The modern Broad band seismograph can sense and record the event from as far as 11,000 Kilo meter. Now you can filter the non seismic records and can find the different from other types of earth shaking. Therefore please believe that the U.S records are reliable. We are sensing of an average of about 2 earthquakes for every 1 minute from some or other parts of the world. But we don’t consider if it is less than 3 in Richter scale. Please remember on a particular day I was sensing very feeble earthquake for hours to gether with the help of earthquake alarm designed by me . After 6 hours noticeable earthquake took place at Andaman. Therefore even minor earthquakes also should be observed for monitoring purpose.I am getting the records reqularly from them.
2007-01-02 18:58:20 · answer #2 · answered by A.Ganapathy India 7 · 0⤊ 0⤋
The vast majority of these events are little tremors deep in the Earth. However, other non-geological events do cause seismic activity. For example, explosions (nuclear, chemical, and other) are often picked up by seismometers.
2007-01-02 11:22:13 · answer #3 · answered by Anonymous · 0⤊ 0⤋
These are mostly earthquakes. We don't worry about them until they get to about 5.
2007-01-02 11:39:44 · answer #4 · answered by Anonymous · 0⤊ 0⤋