3.8 Earthquake In SF Bay Area On Day Celebrating 1906 Quake

Just about five minutes ago, the office where I work out of my home shook just enough for me to wonder if it was a bus crash into the building or an earthquake. One check of Twitter revealed it to be the latter:

CesarQuintero Cesar Quintero
RT @beckyfc: @moshbrown Well, it IS the 105th anniversary of the earthquake that destroyed SF in 1906. Perhaps it was a commemoration quake.
42 seconds ago Favorite Retweet Reply

Yep. On the day when the Bay Area remembers the giant 1906 San Francisco Earthquake and Fire, the earth shook, and it wasn't planned. It was small, some felt it, others did not:

amandamaiyang amanda mai yang
i didn't feel the earthquake, because i have been convulsing from coffee withdrawl
2 minutes ago

Here are the details right from the website of the U.S. Geological Survey:

Magnitude 3.8
Date-Time

Monday, April 18, 2011 at 21:57:19 UTC
Monday, April 18, 2011 at 02:57:19 PM at epicenter

Location 37.597°N, 122.455°W
Depth 13.6 km (8.5 miles)
Region SAN FRANCISCO BAY AREA, CALIFORNIA
Distances

4 km (2 miles) SE (136°) from Pacifica, CA
4 km (2 miles) SW (220°) from San Bruno, CA
5 km (3 miles) W (266°) from Millbrae, CA
10 km (6 miles) S (175°) from Daly City, CA
20 km (12 miles) S (189°) from San Francisco City Hall, CA

Location Uncertainty horizontal +/- 0.2 km (0.1 miles); depth +/- 0.4 km (0.2 miles)
Parameters Nph= 79, Dmin=4 km, Rmss=0.1 sec, Gp= 72°,
M-type=local magnitude (ML), Version=3
Source

California Integrated Seismic Net:
USGS Caltech CGS UCB UCSD UNR

Event ID nc71560691

Stay tuned.