Earthquake Commentary for May, 2000

Map of recent earthquake activity

Send comments and suggestions to:kate@bombay.gps.caltech.edu


09:00 PDT, Wednesday, May 31

A M3.0 Hector Mines aftershock occurred this morning at 4:12 am. The epicenter was located 36 miles north of Joshua Tree. As far as we know, nobody noticed.


21:45 PDT, Friday, May 26

At 8:35 pm this evening the people of Ridgecrest were jolted by a M4.1 earthquake that occurred 11 miles north of the city. We received no formal reports that the earthquake was felt, but due to its size and proximity to Ridgecrest it's more than likely to have been. This evenings earthquake was located roughly 2 miles from the M5.8 Ridgecrest earthquake that occurred on September 20th, 1995.


10:55 PDT, Friday, May 26

The week's earthquake list totals 390 this week. Click here to see a summary and map .


15:03 PDT, Tuesday, May 23

The largest quake in the Olancha sequence, M4.0, occurred at 9:42 pm last night. Like the others, it was located 4 miles northwest of Olancha, along the eastern front of the Sierra Nevada. We do not know if it was felt or not, but presumably it was. The largest previous member of the sequence was M3.5.

Another possibly feelable Olancha quake occurred at 4:11 am, magnitude M3.0.


09:45 PDT, Monday, May 22

On Saturday evening, at 8:40 pm, there was a M3.5 Hector aftershock, located 38 miles north of Joshua Tree. It was, as far as we know, not felt.

Another quake at 11:27 pm Saturday night was felt, however. This one occurred 2 miles north-northwest of Big Bear City, and had a magnitude of M3.7. It was felt in the San Bernardino Mtns., in San Bernardino, and in the Apple Valley area.

A third quake over M3 occurred early this morning at 12:51 am. The epicenter was 13 miles southwest of Ocotillo. Magnitude was M3.1. It was not felt.


16:48 PDT, Friday, May 19

Two more quakes in the Olancha series occurred this afternoon: a M2.7 at 4:06 pm and a M3.5 at 4:07 pm. Like the others, both were located 4 miles northwest of Olancha, along the eastern front of the Sierra Nevada. So far, we have no "felt" reports, but the M3.5 is likely to have been felt.


18:58 PDT, Thursday, May 18

The week's earthquake list totals 397 this week. Click here to see a summary and map .


09:55 PDT, Thursday, May 18

A M3.9 quake occurred at 2:41 am today, located 8 miles east-southeast of Tehachapi. It was felt as far away as Leona Valley and the Lake Isabella area. Although this quake is very close to the Garlock fault zone, the focal mechanism does not agree with the left-lateral strike slip expected from the Garlock.

At 10:37 am on Wednesday, another quake occurred at the swarm site 4 miles northwest of Olancha. This quake was a M3.5, the largest so far. It was accompanied by a few aftershocks in the M1 and M2 range. The previous "largest" was a M3.4 at 2:28 am Wednesday. Neither of these was reported felt.


17:17 PDT, Tuesday, May 16

A M3.4 Hector aftershock occurred early this afternoon, at 1:45 pm. The epicenter was located 38 miles north of Joshua Tree. There were no inquiries.


10:44 PDT, Tuesday, May 16

A small swarm of quakes occurred overnight in the Owens Valley area, 4 miles northwest of Olancha, along the eastern front of the Sierra Nevada. The largest quakes were a M3.0 at 1:56 am and a M2.8 at 6:51 am. We have not gotten any inquiries.


17:24 PDT, Thursday, May 11

The week's earthquake list totals 307 this week. Click here to see a summary and map .


17:03 PDT, Wednesday, May 10

Two noticable quakes occurred this afternoon in the northern Imperial Valley, 1 miles southwest of Obsidian Butte. These were a M3.9 at 4:25 pm and a M3.6 at 4:28 pm. This area is in the Brawley Seismic Zone, which is a zone of faulting and numerous small to moderate sized earthquakes, which connect the northern end of the Imperial fault with the southern end of the San Andreas at Bombay Beach. Several small (less than M3) aftershocks followed.


18:15 PDT, Thursday, May 04

The week's earthquake list totals 344 this week. Click here to see a summary and map .


16:14 PDT, Thursday, May 04

Two potentially feelable quakes occurred today in the Inland Empire. The first was 1 miles west-southwest of Loma Linda, and had a magnitude of M2.8. It occurred at 10:01 am. The second one occurred at 12:53 pm, about 3 miles northeast of Moreno Valley, with a magnitude of M2.7. Both quakes were fairly close to the San Jacinto fault.


08:53 PDT, Thursday, May 04

A M3.0 occurred yesterday at 2:28 pm, near the Garlock Fault 7 miles east-southeast of Tehachapi. There were no inquiries.


16:53 PDT, Tuesday, May 02

There was also some small activity near Obsidian Butte. The largerst was a M2.7 at 8:44 am this morning, located 2 miles east of Obsidian Butte.


09:27 PDT, Tuesday, May 02

There was a swarm south of the U.S./Mexico border overnight, the largest events of which were felt in Imperial Valley. The swarm included a M4.0 at 11:45 pm, a M3.7 at 12:06 am, and a M4.0 at 12:16 am, accompanied by a number of smaller quakes. These magnitudes are preliminary. The epicenters are all about 41 miles south-southeast of Calexico, or 48 miles southwest of Yuma. We will post more details later today.


This page is www.trinet.org/eqreports/comments/May2000.html.
Last updated 09:00 PDT May 31, 2000.