<?php   /* Code: Nyiragongo Equilibrium © Charles Chandler http://qdl.scs-inc.us/?top=16168 */   // distance * thermal expansion per degree * degrees = expansion // distance = expansion / (thermal expansion per degree * degrees) $v['expansion per degree'] = 5 * pow(10, -5); // per &deg;C $v['moho temp' ] = 900; // K, http://www.sciencedirect.com/science/article/pii/S0012821X05001068 $v['lava temp' ] = 1500; // K, (or 1380, per http://www.volcanodiscovery.com/photos/nyiragongo/jan11/lavalake/image10.html) $v['granite temp ave.' ] = (300 + $v['moho temp']) / 2; // K $v['degrees' ] = $v['lava temp'] - $v['granite temp ave.']; // K $v['lava elev' ] = 3.200; // km $v['plain elev' ] = 1.500; // km $v['expansion' ] = $v['lava elev'] - $v['plain elev']; // km $v['moho depth predicted'] = $v['expansion'] / ($v['expansion per degree'] * $v['degrees']); // km $v['moho depth actual' ] = (20 + 28 + 40 + 45) / 4; // km, http://www.sciencedirect.com/science/article/pii/S0012821X12004773, pgs 74, 75   /* Results:   expansion per degree 5.0E-5 moho temp 900 lava temp 1500 granite temp ave. 600 degrees 900 lava elev 3.2 plain elev 1.5 expansion 1.7 moho depth predicted 37.78 moho depth actual 33.25 */   ?>