Earthquake Commentary for May, 1998

Map of recent earthquake activity

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17:32 PDT, Thursday, May 28

We recorded and analysed 144 earthquakes in the past week. Click here to see a summary and map .

16:44 PDT, Thursday, May 28

Finally, after almost a week, we finally have an earthquake worth reporting: a M2.9 at 3:38 pm today. The epicenter was offshore, 14 miles south-southwest of Newport Beach. We have not received any 'felt' calls so far.

We also had a M2.5 at 3:58 pm, located 27 miles north of Yucca Valley. This latter event is a Landers aftershock.

16:54 PDT, Wednesday, May 27

We really are still here and this web site is really still active. We just haven't had any quakes over M2.5!

09:35 PDT, Friday, May 22

At 6:46 am this morning, there was a M3.0 quake in the San Bernardino area. It occurred along the I215, 5 miles north-northeast of Rialto, and it was felt in the epicentral area. The focal mechanism showed 'normal' faulting, which indicates extension of the crust.

17:23 PDT, Thursday, May 21

It's been a slow week; we recorded and analysed 169 earthquakes. Click here to see a summary and map .

16:52 PDT, Wednesday, May 20

We've had two quakes of M2.5 and larger lately inside our Network. The first occurred at 5:25 pm yesterday, 7 miles south-southwest of Idyllwild, in the San Jacinto Fault zone. It had a magnitude of M2.6. The second one was a M2.5, at 4:40 am today, located 9 miles east-southeast of Coso Junction.

If we are slow to respond to earthquake activity, it is because our pagers are not working (nor are anyone else's).

12:34 PDT, Monday, May 18

At 11:11 am today, there was a M2.9 quake, located 7 miles east of Borrego Springs. This area is part of the complex San Jacinto Fault zone. We have not received any reports that the quake was felt.

19:47 PDT, Friday, May 15

There have been a few more Coso Range quakes in the past 24 hours. The largest ones were: a M2.7 at 10:34 pm yesterday and a M2.5 at 3:46 pm today. Both were located 17 miles east of Coso Junction.

17:20 PDT, Thursday, May 14

We recorded and analysed 187 earthquakes in the past week. Click here to see a summary and map .

16:26 PDT, Wednesday, May 13

... and, at 3:47 pm, there was another M2.6, in the Coso Ranges 6 miles east-northeast of Coso Junction.

14:30 PDT, Wednesday, May 13

At 12:40 pm today, there was a small earthquake (M2.6) in the Imperial Valley, 3 miles southeast of El Centro. Like the Imperial Valley quake on Saturday, today's was in the Brawley Seismic Zone.

08:58 PDT, Monday, May 11

Yesterday, I failed to mention a M2.6 Landers aftershock (of the June 28, 1992 Mw7.3 Landers quake) at 9:20 pm on Saturday, located 17 miles north of Yucca Valley. Since this is a very sparsely populated area, I strongly doubt if anyone noticed the quake.

10:33 PDT, Sunday, May 10

There was a M3.5 quake in the Coso Range area this morning at 9:51 am. The epicenter was 8 miles east-southeast of Coso Junction, or about 10 miles west-southwest of the center of the March activity.

13:51 PDT, Saturday, May 09

There have been three small earthquakes of interest since the last update. First, there was a M3.1 at 3:19 am today, located near Obsidian Butte in the Imperial Valley (southern end of the Salton Sea). Obsidian Butte is a common area for earthquake swarms. It falls within a band of seismic activity, known as the Brawley Seismic Zone, connecting the northern end of the Imperial Fault with the southern end of the San Andreas Fault.

The second quake of interest occurred at 5:28 am, near the Agua Dulce Airport, along Rte. I14 in the San Gabriel Mtns. It had a magnitude of M2.6, barely enough to wake a coyote.

The third quake, and the one most likely to have been felt (although we've received no reports), occurred at 9:34 this morning. It was located eight miles south-southwest of Fontana, or, in other words, somewhere between Mira Loma and Glen Avon. The magnitude was also M2.6.

18:20 PDT, Friday, May 08

We had another small quake (M2.8), at 1:43 pm today. It was located 2 miles northwest of Coso Junction, in Rose Valley, which is at the southern end of Owens Valley.

08:35 PDT, Friday, May 08

At 8:44 pm last night, there was a M2.6 Coso quake, located 16 miles east of Coso Junction. This is the region where the swarm occurred in early March.

We recorded and analysed 304 earthquakes in the past week. Click here to see a summary and map .

08:58 PDT, Wednesday, May 06

We got a couple of 'felt reports' for the Orange County area at about 10:50 pm last night. All we recorded at that time, however, was a good-sized sonic boom. Sonic booms, which are sounds waves propagating through the air rather than through the ground as in a real earthquake, are often mistaken for earthquakes.

09:48 PDT, Tuesday, May 05

There was a small quake in the San Gorgonio Pass area at 4:40 pm yesterday. It had a magnitude of M2.8 and was located seven miles east-southeast of Mt. San Gorgonio. As far as we know, it was not felt by anyone.

10:16 PDT, Monday, May 04

We had another small quake in the Coso Range region: a M2.6 at 1:44 am today, located 6 miles east-northeast of Coso Junction, or about 10 miles to the west of the epicenter of the March Coso Range activity.

11:15 PDT, Saturday, May 02

At 10:06 pm Friday night, there was a M2.7 quake in the Point Mugu area, 5 miles west of Leo Carrillo State Beach. We've had no indication to far that it was felt by anyone.

15:05 PDT, Friday, May 01

The excitement for today was a M3.7 Northridge aftershock at 2:02 pm, located 5 miles north-northeast of Simi Valley. Like almost all of the Northridge aftershocks, it had a thrust focal mechanism. It was felt in Simi Valley and the western San Fernando Valley areas.

10:14 PDT, Friday, May 01

We recorded and analysed 260 earthquakes in the past week. Click here to see a summary and map .

Last updated 17:32 PDT May 28, 1998
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