document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=252183>Question 252183</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An earthquake registers 6.1 on the Richter scale. What is the rating on an earthquake that is twice as powerful? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #183955 by </B><A HREF=/tutors/aboutme.mpl?userid=drk><B>drk(1908)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=drk><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=183955\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Richter numbers are based on powers of 10. For example a 7.1 will be 10 time more powerful than a 6.1. Put another way 1og^(7.1-6.1) = 10^1 = 10. Our task is to find what magnitude makes a 2, not a 10. Here we go . . . \r<BR>\n" );
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document.write( "log_10(X) = (a-b) -> in words log_10 = log base 10\r<BR>\n" );
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document.write( "Since we have a magnitude of 6.1, and want an EQ twice as strong,\r<BR>\n" );
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document.write( "log_10(2) = (a-6.1)\r<BR>\n" );
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document.write( "10^(a-6.1) = 2\r<BR>\n" );
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document.write( "By log of both sides,\r<BR>\n" );
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document.write( "a - 6.1 ~ .30103\r<BR>\n" );
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document.write( "a ~ 6.4. </SPAN>\n" );
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