Earthquake Commentary for September, 2002

Map of recent earthquake activity

Did you feel it?

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


11:07 PDT, Sunday, September 29

There was another M3 quake this morning: at 10:46 am, 12 miles south-southwest of Ludlow, magnitude M3.0. It was an aftershock of the October 1999 Hector Mines quake, Mw7.1. We don't have any "felt reports" yet. We might not get any, because of the remote location.

Another, smaller, quake might have been felt. This was a M2.5 at 7:39 pm last night, located 3 miles south east of the town of Big Bear Lake.


12:30 PDT, Saturday, September 28

Well this Saturday morning has been busy, seismically speaking. As of yet there have already been 4 earthquakes greater than M3.0 and it's not even noon! It all started this morning at 3:34 am when a preliminary M3.8 earthquake awoke the people of the western border region of Inyo and San Bernardino Counties. The hypocenter for the quake was located 13 miles north-northeast of Trona and aftershocks are occurring in this general area. The largest two, so far, have been a (prelminary) M3.6 at 11:11am and a M3.2 at 11:12 am. A special Thank You goes out to the two loyal "feelers" - one in Inyokern and one in Ridgecrest - who visited the "Did You Feel It?" webpage (http://pasadena.wr.usgs.gov/shake/ca/) and informed us of the intensities of the quakes. Moving south, a M3.5 earthquake occurred at 9:05 am which was located 31 miles south-east of Calexico. As of yet, there is no word that this earthquake was felt.


11:37 PDT, Saturday, September 28

We have had some seismic action in the Panamint Valley area, east of Owens Valley, overnight. The largest events were: a M3.8 at 3:34 am, a M3.6 at 11:11 am & a M3.2 at 11:12 am. The epicenters are all located 13 miles north-northeast of Trona. These quakes are definitely large enough to have been felt, but the area is very sparsely populated.

Also, at 9:05 am, there was a M3.5 in northern Baja, 31 miles southeast of Calexico. This quake might possibly have been felt in the Imperical Valley and, of course, in the epicentral area in Mexico.


17:15 PDT, Thursday, September 26

We have recorded and located 201 earthquakes in the last week. Click here to see a summary and map .


12:41 PDT, Wednesday, September 25

A very small quake (M1.7) has been felt today in Culver City. The time was 11:59 am & the epicenter was lcoated in Culver City, 2 miles west-southwest of Baldwin Hills.


10:47 PDT, Monday, September 23

Early this morning, at 1:13 am, a quake in Mexico was felt in the Imperial Valley area. This quake had a magnitude of M3.6 & was located 34 miles south of Calexico. There was a M3.1 aftershock nearby at 8:41 am.


07:54 PDT, Monday, September 23

On Saturday, there was a widely felt quake in the Borrego Badlands, 6 miles north of Ocotillo Wells. The time was 2:26 pm & the magnitude was M4.1. Focal mechanism was strike-slip. This quake was felt from the U.S./Mexico border to Corona & Twentynine Palms.


17:23 PDT, Thursday, September 19

We have recorded and located 196 earthquakes in the last week. Click here to see a summary and map .


10:07 PDT, Thursday, September 19

We have another M2.8 in the northern Imperial Valley, about a half mile south of Obsidian Butte, or 9 miles north or Westmorland. The magnitude was M2.8 & the time was 8:59 am. So far, we have no "felt reports".


07:03 PDT, Thursday, September 19

Just after 8:00 pm last night, there was a M2.8 offshore that was widely felt in the South Bay area. The epicenter was located 5 miles west-northwest of Palos Verdes Point. A partial list of town where it was felt are: Palos Verdes Estates, Rancho Palos Verdes, Hermosa Beach, Redondo Beach, Manhattan Beach, Torrance & Gardena. The peak Modified Mercalli intensity was IV.

Also last night, at 11:21 pm, there was a M3.5 Hector Mines aftershock, located 33 miles southwest of Baker or 35 miles east of Barstow. This quake was reported felt in the Victorville area & the Lucerne Valley area. The focal mechanism was strike-slip.


10:40 PDT, Tuesday, September 17

We have recorded a M2.8 aftershock to this morning's M3.6 quake. It occurred at 10:07 am, 8 miles west-southwest of Anza & was felt in Hemet & Temecula.


08:15 PDT, Tuesday, September 17

A M3.6 quake has occurred this morning at 8:00 am. The epicenter was located 7 miles west-southwest of Anza, or 26 miles south-southwest of Palm Springs. "Felt reports" are beginning to trickle in, indicating that the quake was felt as far away as Riverside & Escondido.


07:28 PDT, Monday, September 16

There was a M3.1 Landers aftershock early yesterday afternoon, at 2:15 pm, located 6 miles south-southwest of the town of Joshua Tree. It was felt in Joshua Tree, Desert Hot Springs & Palm Springs.

Just after midnight, a very small quake (M1.8) was felt in the West Los Angeles & Beverly Hills area. The epicenter was 2 miles north-northwest of Culver City & the time was 12:45 am.


17:18 PDT, Thursday, September 12

We have recorded and located 214 earthquakes in the last week. Click here to see a summary and map .


06:13 PDT, Wednesday, September 11

A very small quake was felt at 8:48 pm last night, in Orange County. The quake was a M2.2, located 2 miles northeast of Bolsa Chica Beach. It was felt in Huntington Beach, Seal Beach, Westminster & Cypress.


07:27 PDT, Saturday, September 07

The lastest small quake to be felt occurred 4 miles north of Fontana at 6:24 am this morning. The magnitude M2.8 quake was felt in Rancho Cucamonga, Fontan, Rialto & Lytle Creek, with a peak intensity of Modified Mercalli II (just above "not felt"). This quake is unrelated to the ongoing aftershock sequence in Yorba Linda.


17:57 PDT, Friday, September 06

A pair of M3+ quakes happened close together in time, but far apart in distance, late this afternoon. The first was a M3.2 at 5:02 pm, located 3 miles east of Coso Junction (along Rt. 395, about halfway between Los Angeles and Mammoth). The other one was a M3.2 in northern Mexico at 5:25 pm, 67 miles south-southwest of Ocotillo. Due to their locations, neither of these will probably be reported felt.


15:44 PDT, Friday, September 06

One of the small Yorba Linda aftershocks was felt this afternoon in the Diamond Bar area. The quake was a M2.6 & was location, near the others, 4 miles northeast of Yorba Linda. The time was 3:29 pm.


12:39 PDT, Friday, September 06

Yesterday afternoon at 6:27 pm, a M3.0 quake was felt in the northern Orange County & Inland Empire areas. This quake was an aftershock of Tuesday's M4.8 ("upgraded" from M4.6). The location was the same as all the earlier events, 3 miles northeast of Yorba Linda. It was felt fairly widely, as far away as Pasadena.

There was also a quake near Parkfield last night. It was located by the Northern California Seismic Network to be 5 miles south-southwest of Parkfield, or 20 miles northeast of Paso Robles. The time was 12:28 am & the magnitude was M3.8. It was felt in Paso Robles & the San Luis Obispo area.


18:58 PDT, Thursday, September 05

We have recorded and located 219 earthquakes in the last week. Click here to see a summary and map .


07:54 PDT, Wednesday, September 04

We had a small quake this morning in the San Jacinto fault zone near Anza. The time was 7:44 am & the epicenter was 4 miles north-northwest of Anza or 9 miles south of Idyllwild. The magnitude was M2.8. We have no "felt reports" so far.


13:56 PDT, Tuesday, September 03

A small aftershock of today's Yorba Linda M4.6 was felt at 1:03 pm. The magnitude was M2.6 & the epicenter had the same location as the others, 3 miles northeast of Yorba Linda.


11:39 PDT, Tuesday, September 03

A M4.6 quake, with 2 foreshocks & about 24 aftershocks (so far) shook up the Orange County & Inland Emprire areas this morning. The mainshock occurred at 12:08 am, 3 miles northeast of Yorba Linda & was felt as far as the High Desert region & Escondido. The peak intensity was Modified Mercalli V, which is enough to waken sleepers & knock items off shelves but is unlikely to do any structural damage. The largest foreshock (a M2.6 at 9:50 pm)& two of the largest aftershocks (a M2.9 at 12:15 am & a M2.8 at 4:28 am) were also reported felt in the epicentral region.

Please refer to the special reports (back one page for link) for a map showing the location of the sequence relative to other L.A. Basin quakes in the past year.


This page is www.trinet.org/eqreports/comments/September2002.html.
Last updated 11:07 PDT September 29, 2002.