Yosemite National Park: Rockfall creates 2.5 M earthquake

Wednesday, April 1, 2009

Yosemite National Park: Rockfall creates 2.5 M earthquake

Officials say no one was injured in a giant rockfall near Yosemite National Park's iconic Half Dome, but it did close a trail.

The tumbling boulders unleashed so much fury before daybreak Saturday that the fall registered as a magnitude-2.5 earthquake. The debris fell into Tenaya Canyon and buried the southern portion of the Mirror Lake loop trail.

Park geologist Greg Stock said the avalanche at 5:26 a.m. from Ahwiyah Point was the largest in 10 years, surpassing the October event that forced the park to permanently close part of Curry Village.

View Yosemite rockslide earthquake in a larger map
Google earthquake - rockfall location map

Earthquake Details

Magnitude	2.4
Date-Time	Saturday, March 28, 2009 at 12:26:04 UTC Saturday, March 28, 2009 at 05:26:04 AM at epicenter Time of Earthquake in other Time Zones
Location	37.752°N, 119.540°W
Depth	6.7 km (4.2 miles)
Region	CENTRAL CALIFORNIA
Distances	3 km (2 miles) ENE (72°) from Yosemite Valley, CA 5 km (3 miles) E (81°) from Yosemite Village, CA 31 km (19 miles) SE (135°) from Hetch Hetchy Reservoir, CA 51 km (32 miles) WNW (285°) from Mammoth Lakes, CA 191 km (119 miles) ESE (117°) from Sacramento, CA
Location Uncertainty	horizontal +/- 0.2 km (0.1 miles); depth +/- 3.9 km (2.4 miles)
Parameters	Nph= 65, Dmin=37 km, Rmss=0.15 sec, Gp= 47°, M-type=duration magnitude (Md), Version=2
Source	California Integrated Seismic Net: USGS Caltech CGS UCB UCSD UNR
Event ID	nc40233925

1 comment:

AnonymousSaturday, April 04, 2009 7:53:00 PM
Climbed across this rockfall three days after it happened. The decimation of the forest in the path of the slide left us speechless. Could still hear the occasional rockfall 4 or 5 days later in the middle of the night (at upper pines).
ReplyDelete
Replies

Add comment

CAL FIRE NEWS LOVES COMMENTS...
- Due to rampant abuse, we are no longer posting anonymous comments. Please use your real OpenID, Google, Yahoo, AIM, Twitter, Flickr name.

****REMINDER**** Every fire has the ability to be catastrophic. The wildland fire management environment has profoundly changed. Growing numbers of communities, across the nation, are experiencing longer fire seasons; more frequent, bigger, and more severe, fires are a real threat. Be careful with all campfires and equipment.

"I am a firm believer in the people. If given the truth, they can be depended upon to meet any national crisis. The great point is to bring them the real facts, and beer." --Abraham Lincoln

View blog top tags
---------------------

CLICK HERE TO GO BACK TO TOP OF CALIFORNIA FIRE NEWS HOME PAGE

How fires get their names

Every year in California thousands of wildfires start throughout the state. In most cases, the dispatch center sending the initial resources to a wildland fire will designate a name for the fire, but the first on scene engine or fire official can also name the incident. Fires are usually named for the area in which they start – a geographical location, local landmark, street, lake, mountain, peak, etc. Quickly naming the fire provides responding fire resources with an additional locater, and allows fire officials to track and prioritize incidents by name. For example during the Southern California Fire Siege of 2003, the largest wildland fire in California history, the Cedar Fire in San Diego County, was named after the Cedar Creek Falls area where it started. The destructive Old Fire, which burned during the same time period in San Bernardino County, was named after the road along which it started - Old Waterman Canyon Road.

CAL FIRE is the largest fire department in California and the second largest fire department in the United States. CDF - CAL FIRE Firefighters answer the call more than 300,000 times a year. CAL FIRE Firefighters make up the fire department for 30 of our 58 counties in California and more than 100 local communities. We serve as the incident command during many of California’s most serious disasters. CAL FIRE Firefighters respond to many various types and forms of calls ranging from structural fires, to auto accidents, to earthquakes, to floods, to the spilling of hazardous materials, to every conceivable disaster; CAL FIRE answer's the calls. CAL FIRE is the largest fire department in California and the second largest fire department in the United States . CAL FIRE firefighters protect 33 million acres of State Responsibility Area (SRA). We have over 4,000 members within CAL FIRE and CAL FIRE is associated with the California Professional Firefighters (CPF) and the International Association of Firefighters (IAFF).

CFN - CALIFORNIA FIRE NEWS - CAL FIRE NEWS

Wednesday, April 1, 2009