Evaluation of Don's forecast for the region near Chile
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