By now some of you who watch the California/Nevada earthquake
web site know that it has been an extraordinarily active day in
the Mammoth Lakes region. There have been 6 earthquake of Ml>=2
today (April 24, UT) including one of Ml 2.8 within 32 km of
37.4N 118.7W or 37.5N 118.7W. This sequence started late on
23 May with a Ml 2.1 and extended on through the afternoon of 24 May
with 5 additional events of Ml>=2.0. This is most properly considered
a swarm as there was no clear mainshock.
To put this in perspective, I have done a search in the NCSN
catalog of events within 32 km of either 37.4N 118,7W or 37.5N
118.7W. The last day (UT or PDT/PST) when 6 or more events occurred
with Ml>=2 within this region was more than 1.5 years ago on
November 8, 1999. In other words this is the most active day at
Mammoth Lakes at Ml>=2 levels in 562 days.
What is particularly extraordinary about this is that Don and
Petra called this to the day it began, including a foreshock on
May 21 of Ml 2.8. See message #7544 below for details, reproduced
below.
Since I am something of an unofficial umpire on predictions
posted on this board, and since no one has yet mentioned this,
perhaps waiting for me to break the ice, I am doing so now.

The following is the forecast Don and Petra made on May 15, 2001
which I would say is extraordinary in all details. To those who
say since this forecast is for small events, it doesn't count, I
challenge you to do as well as Don and Petra have done.

In my opinion congratulations are due to Don and Petra on
doing something we all WISH we could do.

Don and Petra's prediction:

Mammoth Lakes Forecast -- Petra and Don
Posted by Don in Hollister on May 15, 2001 at 15:13:00:

Magnitude: 2.0-4.0
From: 05/19/2001 - To: 05/25/2001
Location: Mammoth Lakes
Lat: 37.5N - Long: 118.7W - Range: 32

Hi All. I didn't want to do it this way, but as there seems to be some
confusion as to my post for Mammoth Lakes being a forecast or not I figured
I might as well do it using the form.

I will use the form for the largest of the three quakes being forecasted
which is the 2.5- 4.0Md on 05/23/2001.

So there is no doubt, I'm forecasting three quakes for the Mammoth Lakes area.
One of the other two should be in the area of 37.3N 118.7W on 05/21/2001
with a magnitude of 2.0-3.5. The other one should be in the area of
37.4N 118.7W on 05/23/2001 with a magnitude of 2.3-3-5.

Take Care- Don in creepy town.

Following are today's (UT April 24) events as listed on
http://quake.usgs.gov/recenteqs/Quakes/quakes0.html

MAGNIT YEAR MO DA HR MN SE LATI LONGI DEPTH LOCATION

ML2.2 2001/05/24 13:25:56 37.574N 118.870W 4.6 SE of Mammoth Lakes, CA

ML2.2 2001/05/24 10:17:47 37.574N 118.868W 5.5 SE of Mammoth Lakes, CA

ML2.0 2001/05/24 10:01:30 37.574N 118.868W 5.3 SE of Mammoth Lakes, CA

ML2.0 2001/05/24 06:24:13 37.574N 118.867W 5.1 SE of Mammoth Lakes, CA

ML2.8 2001/05/24 04:46:47 37.572N 118.869W 5.0 SE of Mammoth Lakes, CA

ML2.1 2001/05/23 21:44:37 37.572N 118.868W 5.1 SE of Mammoth Lakes, CA

• California/Nevada earthquakes