An earthquake of Ml 3.1 earthquake occurred about 30 minutes ago
near Saratoga, CA. NCSN is currently giving this event the
following parameters:

ML 3.1 2001/10/05 19:17:33 37.20N 122.03W 10.6 3 km SSW of Saratoga, CA

On August 25, 2001 (post #9611 below) Don had predicted an event as
follows:

30SEP2001 40 km of 37.1N 122.1W ML 2.5-3.5 Ben Lomond, CA
within time window 9/29 to 10/3 and between 37N-37.1N and 122.1-121.3W

This predicted epicenter is less than 15 km from the epicenter
of tonight's event, two days outside the time frame and within the magnitude
limits.

A foreshock to tonight's earthquake had occurred near Saratoga
on 30 September and Don's prediction had been evaluated as an "A"
for that event (See Post #9730 in archives). Tonight's event is
really a much better forecast because:
1) Don's forecast had clearly expected more than one light
earthquake in the region at this time.
2) The event magnitude lies in the middle of Don's given
magnitude range.
and
3) This is the largest earthquake in the 40 km radius Don gave
in nearly 3 years - since December 29-31, 1998. The probability
of a correct forecast within 8 days is thus about 8/1005 or
odds of a "success" of about 1 in 125.

Since Jan 1, 1999 (1005 days), there have been 7 events recorded
of Ml>=2.5 within the 40 km distance set by Don's prediction.
Six periods of 7-days have contained at least one such event of 144
such period. The chance of a "success" within 7 days is thus
6/144 = 0.04. Odds of success are then about 1 in 25. I might add
that since the event occurred 1 day from the predicted date,
the odds of success within 3 days are about 1 in 50. No earthquakes
of Ml>=3 have occurred in this area in this time frame.

Give Don a another grade "A" for this prediction.

Following is Don's complete forecast for this area and event:

"Ben Lomond, Boulder Creek, Santa Cruz, California Earthquake Forecast
Posted by Don In Hollister on September 25, 2001 at 01:13:31:

Magnitude: 2.5-4.0Ml
From: 09/26/2001PDT - To: 10/03/2001PDT
Location: Boulder Creek, California +2
Top Latitude: - Bottom Latitude:
Right Longitude: - Left Longitude:

... I have 3 probable locations. The problem is that one or all could occur
and they also overlap.

The first one is a 2.5-3.5Ml at 37.1N/122.3W. This is about 20Km SSW of
Boulder Creek, California, or just off the coast of California and should
occur on 09/28/2001. Window opens on 09/26/2001 and will close on 10/01/2001.

The second one is a 2.5-4.0Ml at 37.0N122.2W. This is about 8Km NW of Santa
Cruz, California, or just off the coast of California and should occur on
09/30/2001. The window opens on 09/28/2001 and will close on 10/03/2001.

The third one is a 2.5-3.5Ml at 37.1N/122.1W. This is about 3Km NW of Ben
Lomond, California and should occur on 09/30/2001. The widow opens on
09/28/2001 and will close on 10/03/2001. The radius on all quakes is 40Km.

The first two quakes are associated with the San Gregorio Fault. The quake
near Ben Lomond may be associated with the Ben Lomond fault, or the
Zayante-Vergeles fault. The Ben Lomond fault is listed as inactive. The
Zayante-Vergeles has shown activity in the San Juan Bautista area for the
last couple of years. There is another fault in the area and this
is the Butano fault, but this one looks like it may be to far to the NE of
Ben Lomond to be a associated fault.
Take Care....Don in creepy town"

• California Earthquake listing