A swarm of earthquakes centered about 50 miles northwest of Yucca Mountain began Saturday (7/31) night, and was continuing through this posting mid-Monday (8/2). The largest of the 13 quakes over magnitude 3.0 recorded in this series of events measured 5.6 at 9:06 AM local time on Sunday (8/1). This was closely followed, within 21 minutes by two 4.9 events.
The quakes were felt 135 miles to the southeast in Las Vegas, where people reported swaying in Strip high-rise hotels. They were also felt by residents in Fallon, about 260 miles to the northwest. No damage or injuries have been reported.
Seismic records kept since 1910 indicate that the August 1, 5.6 magnitude quake was the third recorded at magnitude 5.0 or greater within 50 miles of Yucca Mountain in that period. A magnitude 5.6 earthquake struck 10 miles southeast of Yucca Mountain, at Little Skull Mountain, on June 29, 1992, and a 5.0 event was recorded about 20 miles west of Beatty on June 13, 1939.
In the past 20 years, there have been over 600 earthquake events of greater than magnitude 2.5 recorded within 50 miles of the proposed Yucca Mountain high-level nuclear waste disposal site.
The following near-real-time Earthquake Bulletin is provided by the National Earthquake Information Service (NEIS) of the U. S. Geological Survey as part of a cooperative project of the Council of the National Seismic System.
Updated as of Mon Aug 2 13:09:51 MDT 1999.
|99/08/01 04:17:13||37.42||-117.05||5||3.9Ml||A||California-Nevada Border Region|
|99/08/01 14:56:40||37.41||-117.02||5||3.8Ml||A||California-Nevada Border Region|
|99/08/01 16:06:22||37.39||-117.07||5||5.6Mb||A||California-Nevada Border Region|
|99/08/01 16:11:20||37.38||-117.03||5||4.9Mb||A||California-Nevada Border Region|
|99/08/01 16:27:16||37.36||-117.05||5||4.9Ml||A||California-Nevada Border Region|
|99/08/02 02:46:26||37.37||-117.05||5||3.3Ml||A||California-Nevada Border Region|
|99/08/02 03:56:08||37.38||-117.07||5||3.4Ml||A||California-Nevada Border Region|
|99/08/02 05:16:03||37.38||-117.08||5||3.0Ml||A||California-Nevada Border Region|
|99/08/02 05:40:26||37.37||-117.03||5||4.1Ml||A||California-Nevada Border Region|
|99/08/02 06:05:12||37.30||-117.04||5||4.9Mb||A||California-Nevada Border Region|
|99/08/02 06:18:58||37.45||-117.04||5||3.4Ml||A||California-Nevada Border Region|
|99/08/02 09:13:37||37.44||-117.02||5||3.2Ml||A||California-Nevada Border Region|
|99/08/02 12:27:11||37.40||-117.06||5||3.0Ml||A||California-Nevada Border Region|
Explanation of earthquake parameters and publication criteria:
Depth in kilometers
MAG - Magnitude, with method used to calculate it:
Ml - local, the original Richter magnitude
Lg - mblg or Mn, local or regional magnitude for the area east of the Rocky Mountains
Md - duration
Mb - body wave
Ms - surface wave
Mw - moment
Q - Earthquake Location Quality: A is good, B is fair, C is poor, D is bad