An earthquake occurred this evening with Ms 6.1 in Guerrero Mexico.
The occurrence of this event may have been influenced by the strong
geomagnetic storm today, as the epicenter fell within 30 degrees of 120W
(at 101W), within the region which was under seismic alert at this time.

Two days ago, the Daily Earthquake summary had noted a string of
Unusual earthquakes occurring across the Central U.S. and had speculated
Regarding the origin of these quakes in the following manner:

"When unusual events occur in short succession across the Central U.S.
they occasionally precede a major event elsewhere. A small circle
from the Saturday events centers in the region about 21.3N 105.8W
on the coast of Jalisco, Mexico. This might be an area to watch
in the next week for a moderate or strong earthquake."

A Ms 6.1 occurred this evening in the region of Guerrero Mexico. The occurrence
Of this event points out not only the value, but the pitfalls of using this type of
Precursor. While the unusual string did appear to have pointed to the occurrence of this event,
The use of only 3 or 4 such events leads to considerable error in the location
Of the epicenter as was the case here. A better forecast might have been
That a strong earthquake was likely in the next 2-3 days (the typical interval
Between this type of string-like precursor and a subsequent mainshock) was
Likely in the region of western Mexico.

• NEIS earthquake listings