Landers and Big Bear California Earthquakes, June 28, 1992
Entry ID:
gov.noaa.ngdc.G01210
|
Summary
ABSTRACT: California residents were rudely awakened early Sunday morning June 28, 1992, by an earthquake of magnitude 7.6 (Ms) followed by a smaller 6.7 (s) magnitude earthquake about three
hours later. The largest shock occurred approximately six miles southwest of Landers, California
and 110 miles east of Los Angeles. The second earthquake was centered approximately eight ... miles southeast of Big Bear City in the San Bernardino Mountains near Barton Flats. A distance of seventeen miles and 7,000 feet in elevation separate the two earthquake locations. In addition to depicting the differences in terrain of the two locations, examples of structural damage, liquefaction, surface faulting, and earthquake generated landslides are illustrated. Statistics - The largest shock occurred
at 4:58 AM PST approximately six miles southwest of Landers, California, and 110 miles east of Los Angeles. Seismicity and Geology - The first shock was the most powerful earthquake in the
contiguous 48 states in forty years. The initial earthquake was reported felt throughout Southern California from the San Luis Obispo to the Mexico Border. It was felt outside California in Idaho, Colorado, New Mexico, and Nevada. The first shock occurred on the north-north-west striking
Camp Rock, Emerson, and Johnson Valley faults and produced a forty-three mile-long surface
rupture zone. In the Landers area there was about ten feet of right-lateral strike slip movement.
The second shock occurred on a separate, previously unknown northeast trending left-lateral strike-slip fault that intersects the Camp Rock-Emerson fault. Scientists are investigating the possibility that these earthquakes may be related to a future event on the San Andreas fault, which together with the faults involved in this series of earthquakes forms a triangle of faults. Damage -
Both earthquakes caused buildings to collapse, ignited fires, buckled roads, damaged water tanks
and crippled water delivery systems, produced numerous rock slides in the San Bernardino Mountains, and derailed standing railroad boxcars near Barstow. The Landers earthquake was directly responsible for the death of a small child who was killed by the collapse of a rock fireplace. Together, the twin earthquakes caused two fatal heart attacks, more than 400 injuries, and left 750 people homeless. Preliminary estimates of property damage in San Bernardino County by officials of the State Office of Emergency Services for the two earthquakes was nearly $100 million, with more than half of the
damage occurring in the Big Bear Lake region. The earthquakes and aftershocks damaged 4,446
homes and 166 businesses; destroyed 77 homes and 10 businesses. Total damage to private
property was estimated at $64.5 million; public facilities reported $25.5 million damage. Roads
and bridges in San Bernardino and Los Angeles counties sustained $500,000 in damage
according to California Department of Transportation. In Riverside County, the losses were
estimated at $950,000; most all of the damage was reported from the City of San Jacinto. Electricity
was knocked out for several hours in the Landers area; in other communities power and
communication links performed well with temporary outages. The damage to the water
storage tanks and the breaks in the distribution system caused water shortages in many areas.
A number of fires resulted from the earth shaking: Two residences burned down completely in
Landers. In Yucca Valley two mobile homes caught fire and one burned down completely. Earth
Effects - Priminary field measurements of movement along the fault line of the 7.5 magnitude earthquake indicate that sections of the fault slipped a maximum of eighteen feet horizontally
and six feet vertically. The width of the rupture zone was reported to range from eleven feet at the narrowest point to 140 feet across at the widest point. Cracks in a dirt road about a mile from
the South Fork campground entrance occurred as a result of the 6.7 magnitude earthquake.
Small water spouts were also observed. The low death toll and structural damage for this series
of earthquakes may be attributed to strengthened building code standards, firm ground, and
wide-open spaces. A single factor that contributed to the low property damage and casualties
was the fact that the force of the earthquake ruptured away from the major population centers.
The Landers-Big Bear earthquake sequence shows that an earthquake on one fault system may
trigger large tremors on other faults in the same area.
PURPOSE: Make available Damage Photos for research and education
CURRENTNESS REFERENCE: Publication Date
Geographic Coverage
Spatial coordinates
| N: 34.2 |
|
S: 34.08 |
|
E: -116.19 |
|
W: -116.8 |
Data Set Citation
Dataset Creator:
DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce (comp)
Dataset Title:
Landers and Big Bear California Earthquakes, June 28, 1992
Dataset Release Date:
1994
Dataset Release Place:
Boulder, CO
Dataset Publisher:
National Geophysical Data Center
Version:
First
Online Resource:
http://www.ngdc.noaa.gov/hazard/
|
Temporal Coverage
Location Keywords
Science Keywords
ISO Topic Category
Project
Access Constraints
ACCESS CONSTRAINTS: None
DISTRIBUTION LIABILITY: While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
Use Constraints
None
Ancillary Keywords
Data Set Progress
Data Center
Distribution
Distribution Format:
TIFF
Fees:
Please See Summary
|
Personnel
JOY
IKELMAN
Role:
TECHNICAL CONTACT
Phone:
303-497-6419
Fax:
303-497-6513
Email:
Joy.A.Ikelman at noaa.gov
Contact Address:
NOAA/NESDIS/NGDC
Mail Code E/GC4
325 Broadway
City:
Boulder
Province or State:
CO
Postal Code:
80303
Country:
USA
KELLY
STROKER
Role:
DIF AUTHOR
Phone:
(303) 497-4603
Fax:
(303) 497-6513
Email:
kelly.stroker at noaa.gov
Contact Address:
NOAA/NESDIS/NGDC E/GC1 325 Broadway
City:
Boulder
Province or State:
CO
Postal Code:
80305-3328
Country:
USA
|
Related URL
Link:
GET DATA
Description:
View all slides in this slide set
|
Creation and Review Dates
DIF Creation Date:
2008-01-18
Last DIF Revision Date:
2008-04-16
|
|
Links
