USGS Earthquake Hazards Program-FAQ - Frequently Asked Questions

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cellspacing="0" cellpadding="0"> <tr> <td><img src="/web/20060117041632im_/http://earthquake.usgs.gov/images/shim.gif" width="1" height="1" alt="spacer"/></td> </tr> </table>  <table width="100%" border="0" cellspacing="0" cellpadding="0" bgcolor="#cccccc"> <tr> <td width="145" valign="top">  <table width="145" border="0" cellspacing="0" cellpadding="5" height="440" bgcolor="#cccccc" background="/web/20060117041632im_/http://earthquake.usgs.gov/images/quakebg.gif" alt="background image"> <tr> <td valign="top"> <center> <p><font color="#cc0000" face="Arial, Helvetica, sans-serif" size="4"><b>Frequently Asked Questions</b></font> </p><hr/> <p><a href="/web/20060117041632/http://earthquake.usgs.gov/faq/"><font face="Arial, Helvetica, sans-serif">FAQ Home</font></a><br/> <a href="/web/20060117041632/http://earthquake.usgs.gov/faq/current.html"><font face="Arial,Helvetica,sans-serif," size="3">Current EQs</font></a><br/> <a 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<tr valign="top"> <td class="bodytext"> <center> <p align="left"><b><font face="Arial, Helvetica, sans-serif" color="#0066FF" size="+2">Historic Earthquakes & Earthquake Statistics</font></b></p> <a name="1" id="1"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">Where do earthquakes occur?</span><br/> </td> </tr> <tr> <td bgcolor="#ffffff"> <p><b>A:</b> <span class="answer">Earthquakes can strike any location at any time. But history shows they occur in the same general patterns year after year, principally in <b>three large zones</b> of the earth. The world's greatest earthquake belt, the <b>circum-Pacific seismic belt</b>, is found along the rim of the Pacific Ocean, where about 81 percent of the world's largest earthquakes occur. The belt extends from Chile, northward along the South American coast through Central America, Mexico, the West Coast of the United States, and the southern part of Alaska, through the Aleutian Islands to Japan, the Philippine Islands, New Guinea, the island groups of the Southwest Pacific, and to New Zealand. This earthquake belt was responsible for 70,000 deaths in Peru in May 1970, and 65 deaths and a billion dollars' damage in California in February 1971. <img src="/web/20060117041632im_/http://earthquake.usgs.gov/faq/images/worldeq.gif" width="361" height="212" align="left" hspace="20" alt="world seismology"/>Why do so many earthquakes originate in this belt? This is a region of young, growing mountains and deep ocean trenches which invariably parallel mountain chains. Earthquakes necessarily accompany elevation changes in mountains, the higher part of the earth's crust, and changes in the ocean trenches, the lower part. The second important belt, the <b>Alpide</b>, extends from Java to Sumatra through the Himalayas, the Mediterranean, and out into the Atlantic. This belt accounts for about 17 percent of the world's largest earthquakes, including some of the most destructive, such as the Iran shock that took 11,000 lives in August 1968, and the Turkey tremors in March 1970 and May 1971 that each killed over 1,000. All were near magnitude 7 on the Richter scale. The third prominent belt follows the submerged <b>mid-Atlantic Ridge</b>.<br/> </span><span class="answer">The remaining shocks are scattered in various areas of the world. Earthquakes in these prominent seismic zones are taken for granted, but damaging shocks occur occasionally outside these areas. Examples in the United States are New Madrid, Missouri, and Charleston, South Carolina. Many years, however, usually elapse between such destructive shocks.</span></p> </td> </tr> </table> <br/> <a name="2" id="2"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">What is the biggest earthquake ever?</span><br/> </td> </tr> <tr> <td bgcolor="#ffffff"> <p><b>A:</b> <span class="answer"> Since 1900, the earthquake in <a href="https://web.archive.org/web/20060117041632/http://neic.usgs.gov/neis/eq_depot/world/1960_05_22.html">Chile on May 22, 1960</a>, is the biggest in the World with magnitude 9.5 Mw.</span></p> </td> </tr> </table> <br/> <a name="3" id="3"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">What is the biggest earthquake in the United States?</span><br/> </td> </tr> <tr> <td bgcolor="#ffffff"> <p><b>A:</b> <span class="answer"> Since 1900, the earthquake in <a href="https://web.archive.org/web/20060117041632/http://neic.usgs.gov/neis/eq_depot/usa/1964_03_28.html">Alaska on March 28, 1964</a>, is the biggest earthquake in the United States, with magnitude 9.2 Mw. This earthquake is also the second biggest earthquake in the World.</span></p> </td> </tr> </table> <br/> <a name="4" id="4"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">Which States in the United States have the most earthquakes?</span><br/> </td> </tr> <tr> <td bgcolor="#ffffff"> <p><b>A:</b> <span class="answer"> <a href="https://web.archive.org/web/20060117041632/http://neic.usgs.gov/neis/states/alaska/alaska.html">Alaska</a> and <a href="https://web.archive.org/web/20060117041632/http://neic.usgs.gov/neis/states/california/california.html">California</a>. </span></p> </td> </tr> </table> <br/> <a name="5" id="5"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">Which State has the most damaging earthquakes? </span> </td> </tr> <tr> <td bgcolor="#ffffff"> <p><b>A:</b> <span class="answer"> California. </span></p> </td> </tr> </table> <br/> <a name="6" id="6"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">Which States have the smallest number of earthquakes?</span><br/> </td> </tr> <tr> <td bgcolor="#ffffff"> <p><b>A:</b> <span class="answer"> <a href="https://web.archive.org/web/20060117041632/http://neic.usgs.gov/neis/states/florida/florida.html">Florida</a> and <a href="https://web.archive.org/web/20060117041632/http://neic.usgs.gov/neis/states/north_dakota/north_dakota.html">North Dakota</a>. </span></p> </td> </tr> </table> <br/> <a name="7" id="7"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">I want to move to a place that doesn't have earthquakes. Where can I go?<br/> </span></td> </tr> <tr> <td bgcolor="#ffffff"> <p><b>A:</b> <span class="answer"> Antarctica has the least earthquakes of any continent, but small earthquakes can occur anywhere in the World. </span></p> </td> </tr> </table> <br/> <a name="8" id="8"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">How many earthquakes worldwide occur each day? Each year? <br/> </span></td> </tr> <tr> <td bgcolor="#ffffff"> <p> <b>A:</b> <span class="answer"> </span></p> <div align="center"> <table border="2" cellspacing="3" cellpadding="2"> <tr align="center"> <th> Descriptor </th> <th> Magnitude </th> <th> Average Annually </th> </tr> <tr> <td> <center> Great </center> </td> <td> <center> 8 and higher </center> </td> <td> <center> 1 </center> </td> </tr> <tr align="center"> <td> Major </td> <td> 7 - 7.9 </td> <td> 18 </td> </tr> <tr align="center"> <td> Strong </td> <td> 6 - 6.9 </td> <td> 120 </td> </tr> <tr align="center"> <td> Moderate </td> <td> 5 - 5.9 </td> <td> 800 </td> </tr> <tr align="center"> <td> Light </td> <td> 4 - 4.9 </td> <td> 6,200 (estimated) </td> </tr> <tr align="center"> <td> Minor </td> <td> 3 - 3.9 </td> <td> 49,000 (estimated) </td> </tr> <tr align="center"> <td> Very Minor </td> <td> < 3.0 </td> <td> Magnitude 2 - 3: about 1,000 per day <br/> Magnitude 1 - 2: about 8,000 per day </td> </tr> </table> </div> <p> </p> </td> </tr> </table> <br/> <a name="9" id="9"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">Where can I find a list of the largest earthquakes in my town?<br/> </span></td> </tr> <tr> <td bgcolor="#ffffff" height="7"> <p><b>A: </b><span class="answer">See <a href="current.html#4">Past Earthquakes</a>.</span></p> </td> </tr> </table> <br/> <a name="10" id="10"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">Where can I find a list of the most destructive earthquakes in the world?<br/> </span></td> </tr> <tr> <td bgcolor="#ffffff"> <p><b>A:</b> <span class="answer"> <a href="https://web.archive.org/web/20060117041632/http://neic.usgs.gov/neis/eqlists/eqsmosde.html">Most Destructive Earthquakes in the World</a></span></p> </td> </tr> </table> <br/> <a name="11" id="11"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">Where can I find a list of the largest earthquakes in the United States? <br/> </span></td> </tr> <tr> <td bgcolor="#ffffff"> <p><b>A:</b> <span class="answer"> <a href="https://web.archive.org/web/20060117041632/http://neic.usgs.gov/neis/eqlists/10maps_usa.html">Ten Largest Earthquakes in the U.S.</a></span></p> </td> </tr> </table> <br/> <a name="12" id="12"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">Where can I find a list of significant damaging California earthquakes?<br/> </span></td> </tr> <tr> <td bgcolor="#ffffff"> <p> <b>A:</b> <span class="answer"><a href="https://web.archive.org/web/20060117041632/http://neic.usgs.gov/neis/eqlists/bigten.lis">Ten Largest Earthquakes in the U.S.</a></span><span class="answer"> </span></p> </td> </tr> </table> <br/> <a name="13" id="13"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">Where can I find other lists of earthquakes?<br/> </span></td> </tr> <tr> <td bgcolor="#ffffff"> <p> <b>A:</b> <span class="answer"><a href="https://web.archive.org/web/20060117041632/http://earthquake.usgs.gov/bytopic/lists.html">Earthquake Lists </a></span><span class="answer"></span></p> </td> </tr> </table> <br/> <a name="14" id="14"></a> <table border="0" width="100%"> <tr> <td bgcolor="#FFCC00"><b>Q:</b> <span class="question">Can I do an earthquake catalog search to get my own list of earthquakes? <br/> </span></td> </tr> <tr> <td bgcolor="#ffffff"> <p><b>A:</b> <span class="answer">See <a href="current.html#4">Past Earthquakes</a>.</span></p> </td> </tr> </table> <p align="center"><a href="index.html">Back to Earthquake FAQ Main page</a></p> </center>  </td> </tr> </table> </td> </tr>  </table>  <table width="100%" bgcolor="#000000" border="0" cellspacing="0" cellpadding="0"> <tr> <td><img src="/web/20060117041632im_/http://earthquake.usgs.gov/images/shim.gif" width="1" height="1" alt="spacer"/></td> </tr> </table> <table width="100%" border="0" cellspacing="0" cellpadding="5" bgcolor="#FFFFFF"> <tr valign="top"> <td> <p> <font color="#000000" size="2" face="Arial, Helvetica, sans-serif" class="footer"> <a href="https://web.archive.org/web/20060117041632/http://www.doi.gov/">U.S. Department of the Interior, </a><a href="https://web.archive.org/web/20060117041632/http://www.usgs.gov/">U.S. Geological Survey</a><br/> This page is brought to you by the Earthquake Hazards Program<br/> URL: http://earthquake.usgs.govfaq/<br/> Maintained by: Web Team<br/> Last modification: Wednesday, 20-Oct-2004 9:05 <br/> Contact Us:<a href="/web/20060117041632/http://earthquake.usgs.gov/cgi-bin/sitemail1.cgi?docname=Web_Team">  Web_Team</a><br/> <br/> USGS <a href="https://web.archive.org/web/20060117041632/http://www.usgs.gov/privacy.html">Privacy Statement</a> | | <a href="https://web.archive.org/web/20060117041632/http://www.usgs.gov/disclaimer.html">Disclaimer</a> | | <a href="https://web.archive.org/web/20060117041632/http://www.usgs.gov/foia/">FOIA</a> | | <a href="https://web.archive.org/web/20060117041632/http://www.usgs.gov/accessibility.html"> Accessibility</a></font> </p> </td> <td> <div align="right"><a href="https://web.archive.org/web/20060117041632/http://firstgov.gov/"><img src="/web/20060117041632im_/http://earthquake.usgs.gov/images/first_gov.gif" width="160" height="47" alt="First Government graphic" border="0"/></a></div> </td> </tr> </table> <span class="tabs"></span> </body> </html>

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USGS Earthquake Hazards Program-FAQ - Frequently Asked Questions