Earthquake rattles Mammoth Lakes area and Yosemite National Park (24/08/2011)

Earthquake overview : At 5 AM in the night on August 24 2011, an earthquake measuring 4.2 magnitude struck the greater Mammoth Lakes area.
We ask people who have felt this earthquake to share their information with our many readers (also from your area). Please use the "I Have Felt it" form below.

Epicenter area at Dorothy Lake - Panoramio image courtesy jbibsss -

Based on the theoretical values of USGS 6 people would experience a moderate shaking, 9,000 people a light shaking and 59,000 people a weak shaking.
The "Felt" area was more or less along the high sierra and extending from the southeast to the northwest.
The earthquake was also felt in Yosemite National Park ans some people even felt it as far as Carson City, Fresno and Lone Pine.
As you can see on the USGS graphic at right, the present epicenter location is among the most active and vulnerable in the sierra.
After checking our many sources, we could not detect any damage or injuries.

In May 1980, the same area (epicenters  from within a radius of 5-10 miles) was hit by 4 separate earthquakes ranging from 6.0 to 6.2. 3 of them occurred at May 25 and 1 at May 27.
Let us hope that this sequence will not come back again.
This is the list of the different shocks :
M 6.2, May 27, 1980 14:50:56 UTC - Depth: 16.09 km (10.00 mi)
M 6.1, May 25, 1980 19:44:50 UTC - Depth: 14.20 km (8.82 mi)
M 6.1, May 25, 1980 16:33:44 UTC - Depth: 9.01 km (5.60 mi)
M 6.0, May 25, 1980 16:49:27 UTC - Depth: 8.67 km (5.39 mi)

Seismic Hazard map Mammoth Lakes and High Sierra courtesy USGS

"I Have Felt It" reports as received by
MMI values (if indicated) after the text (III: Weak shaking, IV Light shaking, V Moderate shaking, VI Strong shaking, VII Very Strong shaking)

East Sonora Califoria - 5am 8/24/11 I was sitting in my tiny livingroom.  Walls started shaking, Pictures on wall slipped back and forth.  Kitchen cabnets shook.  Hanging coffee cups swung back and forth.  Am I the only one who felt this?  I came here 11 years ago from the Bay Area.  I lived through the Loma Pre eta quake.  I did not know that Sonora got earth quakes.  First one I've felt here. Yvonne Kennedy - MMI V
Yosemite, CA - We are on vacation in Yosemite and everyone thought it was a bear we all woke up and determined it was an earthquake. It was a 4.2 in Yosemite and a 4.5 in the epicenter at mammoth lakes - MMI V
Gull lake, CA - quick shake as if someone was started while sleeping.  I was sleeping in a popup trailer along gull lake.   take care - MMI V

Most important Earthquake Data:
Magnitude : 4.2
UTC Time :  Wednesday, August 24, 2011 at 11:59:51 UTC
Local time at epicenter :  Wednesday, August 24, 2011 at 04:59:51 AM at epicenter
Depth (Hypocenter) : 10 km
Geo-location(s) :
14 km (9 miles) SE (137°) from Mammoth Lakes, CA
17 km (11 miles) W (264°) from Toms Place, CA
28 km (18 miles) WNW (301°) from Round Valley, CA
Approx. 50 km from Yosemite NP village
254 km (158 miles) ESE (115°) from Sacramento, CA

Links to important maps
Did You Feel It Map
Google satellite map of the area showing the kind of terrain the earthquake took place
3-dimensional view of the earthquake area (USGS epicenter location)
USGS historic earthquakes map
USGS Seismic hazard map

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I did feel it – Ik heb het gevoeld – Το έκανα αισθάνεται – Yo lo siento – 我的确感到了 – 私はそれを感じていました- Ich habe es gefühlt – Bunu hissediyorum yaptı – لم أشعر أنه


  1. Camping in our rv at convict lake campground when it hit. First time I've heard an earthquake. It sounded like a shotgun blast echoing through the canyon followed by strong shaking. Rocked the rv preaty good for about 20 seconds and knocked coffee cups off counter.