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- February 16, 1995
-
- Weekly Earthquake Report for Southern California
- ------------------------------------------------
- February 9 - 15, 1995
-
- Prepared by: Kate Hutton, Seismological Laboratory
- (kate@bombay.gps.caltech.edu)
- Lucy Jones, U.S. Geological Survey
- California Institute of Technology
-
- For further information, please contact the authors or the Caltech
- Public Relations Office at 818-395-6326. For daily updates, call
- our Earthquake Information Hotline: 818-395-6977.
- --------------------------------
- This week's Report covers the time period from midnight Thursday
- morning, February 9, Pacific Standard Time, to midnight
- Wednesday night, February 15, 1995, Pacific Standard Time. We
- recorded 263 earthquakes of M1.0 or larger during the 7-day period
- covered.
- Just about the only excitement this week was caused by
- the two "Valentine's Day earthquakes" on Tuesday night. Both
- were aftershocks of the Northridge earthquake, and both were close
- to Granada Hills, although not at the same location. The first
- and largest was a M3.2 at 6:54 pm, and the second was a M2.7 at
- 12:40 the next morning. There was initially some confusion with
- the 6:54 pm quake, since our automatic location software failed
- to locate it properly and, due to the poor location, failed to
- notify the duty seismologist. Also possibly because of the poor
- location, the magnitude was underestimated at M2.9. Other things
- besides quakes can affect our signals, including electronic problems,
- wind, and what we call "cultural noise" like traffic, etc. Because
- of these problems, one percent or so of the quakes have problems in
- the automatic locator. We are continually trying to improve the
- percentages, but it's something to watch for if you are a user of
- "finger quake@scec.gps.caltech.edu". In the case of the Granada
- Hills quake, we had improved information going out within a half
- hour.
- Procedures went much more smoothly with the 12:40 am quake,
- although sometimes we wish folks would wait until 8 am to call about
- quakes that tiny!
- Speaking of tiny, we got one call about a M2.2 near Simi
- Valley on Sunday night. We don't know whether to believe it was
- truly felt or just a coincidence that someone called at the right
- time.
- The table lists the quakes this week that were M2.0 or
- larger in the central part of the coverage area. Times are local
- times; if you want Greenwich Mean Time, add 7 hrs to the Pacific
- Daylight Time or 8 hrs to the Pacific Standard Time listed.
-
- Table 1
- -------
- Date Time N Lat. W Long. Mag
- -------------------------------------------------------------
- 2/9 2:30 am 36 28.8 120 29.6 3.1 24 mi. NNW of Coalinga
- 2/9 5:18 am 34 38.1 116 33.2 2.1 25 mi. ENE of Lucerne Valley
- 2/9 7:38 am 34 16.4 118 22.7 2.3 3 mi. E of San Fernando
- 2/9 9:58 pm 36 0.2 119 22.5 2.3 22 mi. SSW of Visalia
- 2/10 2:02 am 32 34.1 117 59.5 2.2 26 mi. SE of San Clemente Is.
- 2/10 4:53 am 34 2.9 117 16.9 2.3 1 mi. SE of the I10/I215
- interchange/Loma Linda
- 2/10 11:48 am 34 24.7 116 28.6 2.1 20 mi. N of Yucca Valley
- 2/10 12:28 pm 33 14.9 116 21.9 2.2 Under Borrego Springs
- 2/10 5:46 pm 35 4.5 118 23.8 2.2 4 mi. SE of Tehachapi
- 2/11 7:00 am 35 33.2 118 54.3 2.0 12 mi. NNE of downtown
- Bakersfield
- 2/11 7:14 am 33 18.8 117 52.7 2.0 16 mi. SSW of Laguna Beach
- 2/11 12:46 pm 35 55.8 117 40.0 2.3 17 mi. ESE of Coso Junction
- 2/12 2:02 am 33 20.6 116 47.3 2.1 4 mi. E of Palomar
- Observatory
- 2/12 2:36 am 36 24.8 120 21.8 2.7 19 mi. N of Coalinga
- 2/12 6:00 am 34 8.7 116 25.4 2.1 2 mi. NE of Yucca Valley
- 2/12 6:29 am 32 48.4 116 8.8 2.3 10 mi. WNW of Ocotillo
- 2/12 6:35 pm 35 50.5 118 19.6 2.1 16 mi. NNE of the town of
- Lake Isabella
- 2/12 8:42 pm 34 21.4 118 41.3 2.2 5 mi. NNE of Simi Valley
- FELT?
- 2/12 8:43 pm 34 38.8 116 31.8 2.5 27 mi. ENE of Lucerne Valley
- 2/13 6:00 am 34 23.9 116 27.3 2.4 19 mi. N of Yucca Valley
- 2/13 2:02 pm 35 12.0 120 49.8 2.8 11 mi. S of Morro Bay
- 2/13 2:37 pm 35 50.5 118 19.6 2.8 16 mi. NNE of the town of
- Lake Isabella
- 2/13 4:14 pm 34 17.6 118 27.2 2.0 1 mi. NW of San Fernando
- 2/13 5:22 pm 32 48.9 118 18.0 2.1 2 mi. E of San Clemente Is.
- 2/14 1:48 am 34 54.8 116 55.7 2.2 5 mi. ENE of Barstow
- 2/14 6:09 am 35 31.6 118 15.1 2.5 14 mi. ESE of the town of
- Lake Isabella
- 2/14 7:25 am 36 11.7 118 18.3 2.6 17 mi. WSW of Olancha
- 2/14 3:08 pm 35 12.1 120 52.9 2.4 11 mi. S of Morro Bay
- 2/14 6:54 pm 34 15.2 118 28.8 3.2 2 mi. SE of Granada Hills
- FELT
- 2/15 12:40 am 34 15.0 118 30.4 2.7 1 mi. S of Granada Hills
- FELT
- 2/15 4:48 am 36 23.1 117 58.7 2.1 7 mi. NNE of Olancha
- 2/15 7:38 am 34 34.1 116 35.6 2.1 21 mi. ENE of Lucerne Valley
- 2/15 10:05 am 36 59.4 117 34.8 2.2 35 mi. NW of Stovepipe Wells
- 2/15 5:10 pm 34 7.2 116 23.9 2.1 2 mi. E of Yucca Valley
- 2/15 10:33 pm 33 52.0 118 16.5 2.0 Near the I110/I405
- interchange
- -------------------------------------------------------------