Earthquake Commentary for September, 2001

Map of recent earthquake activity

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20:11 PDT, Sunday, September 30

Three unrelated small quakes of interest occurred overnight:

The first was a M3.0 at 11:51 pm last night, 4 miles southeast of Mt. San Gorgonio (in the San Gorgonio Pass area).

The second was a M2.9 at 4:50 am this morning, 9 miles south of Taft, or 35 miles southwest of Bakersfield.

The third was a M2.9 at 5:32 am this morning, in the Brawley Seismic Zone (Imperial Valley), 2 miles east-northeast of Obsidian Butte. Since they were all in sparsely inhabited areas, we have not "felt" reports.

17:27 PDT, Thursday, September 27

We have recorded and located 268 earthquakes in the last week. Click here to see a summary and map .

08:58 PDT, Thursday, September 27

At 6:49 pm last night, a M2.8 quake was felt in San Marino and vicinity. The epicenter was located 1 miles southwest of San Marino, actually about 1 mile north of the San Gabriel Mission, not far south of the Raymond Hill fault. A short list of towns where the quake was felt include: San Marino, San Gabriel, South Pasadena, Alhambra, Pasadena, Rosemead, Arcadia, Temple City, Monterey Park, Sierra Madre, Glendale, Montebello, and Los Angeles.

07:21 PDT, Wednesday, September 26

At 6:37 am this morning, we had a M2.8 Hector aftershock, located 17 miles north-northwest of Twentynine Palms. Almost none of the Hector aftershocks smaller than about M3.5 were reported felt, and this one is probably no exception.

12:00 PDT, Tuesday, September 25

There has also been a M3.0 quake 12 miles northeast of Olancha (southern Owens Valley), at 11:34 am today. As with the Coso quake earlier this morning, we have received no "felt" reports.

07:01 PDT, Tuesday, September 25

There was a small quake in the Rose Valley area, 3 miles northeast of Coso Junction, early (4:35 am) this morning. The magnitude was M3.0. As is usual for quakes in this area, we have no "felt" reports.

14:35 PDT, Monday, September 24

The Anza quake yesterday afternoon was felt in Hemet.

Another small quake has been felt in Orange County this morning. Its magnitude was M2.3, and it occurred at 8:17 am this morning, 3 miles north of Orange. It was felt slightly in Orange, Fullerton, Anaheim, Anaheim hills, and Placentia.

07:39 PDT, Monday, September 24

On Sunday afternoon, at 3:44 pm, there was a M3.0 quake in the San Jacinto fault zone 9 miles east-southeast of Anza. It could possibly have been felt, but we don't have any reports as yet.

17:34 PDT, Thursday, September 20

We have recorded and located 242 earthquakes in the last week. Click here to see a summary and map .

16:54 PDT, Thursday, September 20

There has been a small quake, M3.1, located offshore 28 miles southwest of Oceanside. The time was 4:43 pm. Because of the location, it was probably not felt.

07:24 PDT, Monday, September 17

A small quake (M3.1) was felt in the Chino/Puente Hills area yesterday at 6:14 pm. The epicenter was located three miles northeast of Yorba Linda.

17:41 PDT, Thursday, September 13

We have recorded and located 279 earthquakes in the last week. Click here to see a summary and map .

16:50 PDT, Thursday, September 13

Another small aftershock was felt just after noon today, at 12:29 pm. The magnitude was M2.0 and the quake was centered 2 miles southeast of Beverly Hills. Felt reports came from Beverly Hills and Los Angeles.

07:21 PDT, Thursday, September 13

A small quake was felt last night in the Inland Empire area. The time was 7:21 pm and the location was 5 miles north-northeast of Running Springs. The quake was felt in Running Springs itself.

08:10 PDT, Tuesday, September 11

Two more small quakes happened overnight. The first, at 2:10 am, was an aftershock of Sunday's M4.2 West Hollywood/Beverly Hills quake. It's magnitude was M2.2, and it was felt by a few people in the epicentral area.

The second occurred at 5:43 am, offshore 14 miles south of Long Beach. Magnitude was M2.4.

11:09 PDT, Monday, September 10

A M3.0 quake happened this morning at 10:40 am, 7 miles south-southeast of the town of Anza. The only "felt" report we have so far is from Temecula. This quake was located a few miles to the southwest of the San Jacinto fault zone, but it is in an area that has been a long-time source of small quakes.

07:46 PDT, Monday, September 10

There have been a total of nine aftershocks to West Hollywood quake, so far. The largest is still the M2.8 that occurred right after the mainshock. All the aftershocks since 8 pm last night (ranging from M1.4 to M1.8) were probably too small for anyone to feel.

Notice that we have posted a short "special report" on the quake. Go "Back" once and follow the Special Report link.

19:00 PDT, Sunday, September 09

The big seismic news today is a M4.2 that occurred just before 5:00 pm, located 1 miles south-southeast of West Hollywood. It was felt widely in the Los Angeles basin and as far away as Palmdale. Although (as is often the case with quakes this small) we have not yet been able to assign the blame to a particular fault, we do know that the focal mechanism shows stike-slip or horizontal motion on the fault. There were a handful of small aftershocks. The largest, a M2.8 within two minutes after the quake, was felt be people in the epicentral area.

Earlier this weekend, at 9:25 pm Friday night, a M3.1 quake was felt by a few people in the Inland Empire. That quake was located in Cajon Pass, 7 miles northwest of Devore.

18:01 PDT, Thursday, September 06

We have recorded and located 319 earthquakes in the last week. Click here to see a summary and map .

07:43 PDT, Tuesday, September 04

Two more small quakes occurred on Monday. At 6:19 am, there was a M2.8 offshore, 14 miles southwest of Santa Barbara Island. My guess is that, due to its remote location, this quake probably was not felt. A better candidate to be felt was the M2.9 at 11:13 am Monday, 3 miles west-southwest of Valencia.

I did not mention the M3.7 near Coalinga on Sunday, because it occurred within the Northern Californa Seismic Network. It's epicenter was located 7 miles northeast of Coalinga, and it was felt in Coalinga.

10:14 PDT, Monday, September 03

Another quake, M3.1, occurred this morning at 2:55 am. Like the one on Saturday, it was located 14 miles north-northwest of Borrego Springs, in the complex San Jacinto fault zone.

18:03 PDT, Sunday, September 02

At 5:05 pm yesterday (Saturday, Sept. 1), a M3.5 quake occurred in the complex San Jacinto fault zone 9 miles north-northwest of Borrego Springs. The quake was widely felt from San Diego to Palm Springs.

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Last updated 20:11 PDT September 30, 2001.