Posts Tagged ‘aftershock’

Magnitude 4.0 Earthquake Struck UC Berkeley at 2:41 PM, October 20th 2011 – 3.8 Aftershock at 8:16 PM

Thursday, October 20th, 2011

[Or rather, make that a 4.0 on the Richter, final answer. That was for the afternoon earthquake. This evening's aftershock at 8:16 PM was a 3.8.]

People in the West Bay could definitely feel this this one today, the one centered beneath UC Berkeley.

It felt like a succession of sharp bumps for a few seconds and then there was some generalized shaking – perhaps it all lasted about six seconds.

The Did You Feel It Map:

The initial estimate was a 4.2:

Magnitude 4.2
Date-Time
  • Thursday, October 20, 2011 at 21:41:04 UTC
  • Thursday, October 20, 2011 at 02:41:04 PM at epicenter
Location 37.864°N, 122.249°W
Depth 9.8 km (6.1 miles)
Region SAN FRANCISCO BAY AREA, CALIFORNIA
Distances
  • 2 km (2 miles) ESE (112°) from Berkeley, CA
  • 5 km (3 miles) NE (47°) from Emeryville, CA
  • 5 km (3 miles) NNW (341°) from Piedmont, CA
  • 8 km (5 miles) NNW (346°) from Oakland, CA
Location Uncertainty horizontal +/- 0.2 km (0.1 miles); depth +/- 0.4 km (0.2 miles)
Parameters Nph= 90, Dmin=2 km, Rmss=0.18 sec, Gp= 22°,
M-type=local magnitude (ML), Version=3
Source
Event ID nc71667366

Minor Bay Area Earthquake of June 6, 2009 – 3.2 on the Richter Scale

Saturday, June 6th, 2009

We certainly could sense it in San Francisco, anyway, but it definitely was smaller than what occurred on March 30, 2009.  No reports of injuries or damage so far.  See the deets below. It felt very small in San Francisco. It felt “short and sharp” to those a mile away from the epicenter in the East Bay. At least one “weenie Texan” transplant “thought it was a five.” And Commenter Jane says “It felt like a big truck drove up the street in Point Richmond.”

Those in the State Building in San Francisco’s Civic Center probably didn’t feel a thing. Mayor Gavin Newsom would probably like to remind you about upgrading your “soft story” structure. And good thing City Attorney Dennis Herrera is Suing  for Seismic Safety Upgrades at the Mirant Power Plant, right?

Gaia is stirring…

 quake

An earthquake occurred at 3:30:56 PM (PDT) on Saturday, June 6, 2009.
The magnitude ? (not yet determined) event occurred 1 km (1 miles) NE of El Cerrito, CA.
The hypocentral depth is 6 km ( 4 miles).


Magnitude 3.2
Time Saturday, June 6, 2009 at 3:30:56 PM (PDT)
Saturday, June 6, 2009 at 22:30:56 (UTC)
Distance from El Cerrito, CA – 1 km (1 miles) NE (37 degrees)
Kensington, CA – 2 km (2 miles) NNW (330 degrees)
East Richmond Heights, CA – 3 km (2 miles) SE (139 degrees)
Berkeley, CA – 6 km (4 miles) NNW (345 degrees)
Oakland, CA – 16 km (10 miles) NNW (339 degrees)
Coordinates 37 deg. 55.5 min. N (37.925N), 122 deg. 17.6 min. W (122.293W)
Depth 6.1 km (3.8 miles)
Location Quality Excellent
Location Quality Parameters Nst= 25, Nph= 25, Dmin=4 km, Rmss=0.1 sec, Erho=0.2 km, Erzz=0.5 km, Gp=39.6 degrees
Event ID# nc40237749
Additional Information map with fault names
Google Earth KML (Requires Google Earth.)
Waveforms

The Minor Bay Area Earthquake of March 30, 2009 – a 4.3 on the Richter Scale

Monday, March 30th, 2009

That didn’t feel so bad in the 415. A little scary at first, for a second or two. After that you could tell it wasn’t going to be a big deal…

Magnitude 4.3
Date-Time
  • Monday, March 30, 2009 at 17:40:29 UTC
  • Monday, March 30, 2009 at 10:40:29 AM at epicenter
Location 37.285°N, 121.620°W
Depth 6.2 km (3.9 miles)
Region NORTHERN CALIFORNIA
Distances
  • 18 km (11 miles) N (7°) from Morgan Hill, CA
  • 19 km (12 miles) E (91°) from Seven Trees, CA
  • 20 km (13 miles) ESE (117°) from Alum Rock, CA
  • 25 km (16 miles) ESE (104°) from San Jose City Hall, CA
Location Uncertainty horizontal +/- 0.1 km (0.1 miles); depth +/- 0.3 km (0.2 miles)
Parameters NST=250, Nph=250, Dmin=7 km, Rmss=0.08 sec, Gp= 58°,
M-type=duration magnitude (Md), Version=1
Source
Event ID nc40234037