D.O.'s+Earthquake+1

Back to Ligo Data Back to Identified Earthquakes LIGO Project Instructions September 05 Data

__** The earthquake taking place at about 8:30 is my first earthquake at -56.4100 -142.3920 in the south of the Pacific Ocean.
 * __Earthquake 1

Here is a map of where the earthquake is. media type="googlemap" key="http://maps.google.com/maps/ms?hl=en&ie=UTF8&msa=0&msid=101783471959187101034.00044b1d66e2a1ee4368c&ll=-56.41,-142.392&spn=0,0&output=embed&s=AARTsJpIaqha5ptFW2u_8DMDZTPCIp0Spg" width="425" height="350"

As you can see from the placement of the earthquake above, it is traveling through water for almost all of the time, so to calculate how long it took to get to LIGO, we will use P-waves. P-waves typically travel between 5-8 km/s according to the Purdue site for earthquakes, and the same will also go for the two other earthquakes I have identified. The total distance was about 11,606 km.

Below is the information for my earthquake and the math to prove that it is a match.

Date Time Lat Lon Depth Mag Magt Nst RMS SRC Event ID

2005/09/05 07:37:31.31 -56.4100 -142.3920 10.00 6.20 Mw 151 1.33 NEI 200509054022

Take the total distance (11,606 km) divided by 6 km/s (the average speed of P-waves) and you get about a 1,934 sec. journey. Now divide the 1,934 sec. by 60 sec. to get about 32 min. which is how long it took to reach LIGO.

You can see that the eastimated time of arrival is actually a little before when LIGO detected it, but if you remember in my calculations that I only used the average speed of P-waves, but they can travel slower than 6 km/s, and in fact they even travel slower when they travel through land. So, if you look closely at the map it actually travels through about 900 km of land before it hits the LIGO detectors so that even adds some more time to it's journey making this earthquake a match!