Posted by Lowell on November 23, 2001 at 20:45:03:
I'm getting way behind on Don's forecasts. So I'll try to catch up little by little. Here is some analysis of the three forecasts he made for Chile and the East Pacific Rise west of Chile. In developments on several earthquake forecasts Don in Hollister has posted QED is now listing the following events in the area of Chile: 1. 19NOV2001 09:20:41 30.0S 71.5W MD=3.9 QED NEAR COAST OF CENTRAL CHILE. 2. 18NOV2001 18:22:00 36.4S 72.6W MD=4.2 QED NEAR COAST OF CENTRAL CHILE. 3. 12NOV2001 01:15:47 36.9S 96.0W MB=4.3 QED WEST CHILE RISE Don had anticipated earthquakes as follows: 1. Nov 15-19 2001 29.9S 72.0W MB 3.4-4.9 Central Chile (65 km radius) 2. Nov 13-17 2001 37.7S 73.0W Mb 3.4-4.9 Central Chile (65 km radius) 3. Nov 15-19 2001 36.0S 98.0W Mb 4.2-5.7 West Chile Rise (65 km radius). The match between prediction and forecast (1) is quite good being within the expected magnitude range, time window and ths prediction within 45 km of the located epicenter. A success in all regards, this is a grade "A" forecast. Number (2) is located about 140 km from the predicted epicenter and lies one day outside the forecast window, but is within the given magnitude range. Not too bad, but we need to check the probability to see if this is better than random. Number (3) likewise is located about 190 km to the SE of the expected epicenter and three days out of the predicted range. Given the background seismicity of the area, this again, may not be a bad prediction, so we need to check the probabilities. Probability on (1): In the past 3 years (since Nov 1, 1998 - 1095 days) there have been 14 of 219 total 5-day periods which have contained an earthquake matching the parameters Don set for this forecast. The probability of random success is thus: 14/219 = 0.06 or odds of success about 1 in 16. An excellent forecast for an area of relatively low seismicity. Grade "A" Probability on (2) Since the forecast was not successful because the occurring event was farther than anticipated from the forecast epicenter, the probability of success with the expanded radius of 150 km and window length of 6 instead of 5 days is found. By doing this, we hope to give the predictor information which might be helpful in adjusting future prediction for successful outcomes. If Don had chose a radius of 150 km and a window length of 6 days, his prediction would have been successful - what would have been the probabilities of random success on this. There have been 20 6-day periods in the past 1095 days (182 6-day periods). So the probability of random success is 20/182 = 0.11, or odds of about 1 in 9 for success. Don could have expanded his windows and still beat the odds considerably. Grade "B" on this forecast. Probability on (3) Again the forecast was only partially successful. This time we would like to see the probability of random success given a 200 km radius and a 9-day time window. During the past 3 years there have been 13 9-day windows which contained an event within 200 km radius and within the magnitude range predicted by Don. In the same period there have been 121 9-day periods, so the probability of random success with such a forecast is 13/121 = 0.11 or odds of 1 in 9 for success given the expanded radius and time window. Once again, Don would have beat the odds considerably if he had used expanded time and radius parameters. Incidentally in the past 10 years there have only been 9 events which lay within 65 km of Don's predicted epicenter, so a success would have beat odds of about 1 in 81 for success. Grade "B" on this forecast. Don's Original forecasts had read: Chile (Post #10802, Posted Nov. 9, 2001) La Serena, Chile Earthquake Forecast Posted by Don In Hollister on November 09, 2001 at 11:30:55: Magnitude: 3.4-4.9Md From: 11/15/2001UTC - To: 11/19/2001UTC Location: La Serena, Chile Lat: 29.9S - Long: 72.0W - Range: 65Km Hi All. It seems no matter what I do I can't seem to get out of the water. At least I'm not in as deep as I was at the other location. The raw onion and garlic sandwiches are okay, but I think I need to find another chaser. Looking for a 3.4 to 4.9Md quake at 29.9S/72.0W. This is about 60Km west of La Serena, Chile. It should occur on 11/17/2001. The window opens on 11/15/2001 and will close on 11/19/2001. The radius on this is 65Km. If there is a moderate to strong geomagnetic storm on or about 11/13/2001 a quake could occur at 37.7S/73/0W on 11/15/2001. This is about 60Km ESE of Los Alamos, Chile. The magnitude should be 3.4 to 4.9Md. On the remote chance that the most recent geomagnetic storm has had an affect on this area the window opens on 11/13/2001 and will close on 11/17/2001. The radius is 65Km. Take Care...still in deep water Don And the West Chile Rise forecast (Post #10788, Nov. 8, 2001): East Pacific Rise Earthquake Forecast Posted by Don In Hollister on November 08, 2001 at 22:28:37: Magnitude: 4.2-5.7Mb From: 11/15/2001UTC - To: 11/19/2001UTC Location: East Pacific Rise Lat: 36.0S - Long: 98.0W - Range: 65Km Hi All. I'm getting into deep water with this one. Like I'm up to my chin so don't anyone create a wave. I'm looking for a 4.2 to 5.7Mb at 36.0S/98.0W. This is the East Pacific Rise. It should occur on 11/17/2001. The window opens on 11/15/2001 and will close on 11/19/2001. The radius on this will be 65Km. Take Care...Don in deep water
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