Significant earthquakes of 1979

October 15, 1979 Earthquake: Mexicali, Imperial Valley, Mexico, California, United States

October 15, 1979 · M6.9 · $30 million · 2 houses destroyed

A magnitude 6.9 earthquake struck Mexicali, Imperial Valley, Mexico, California, United States on October 15, 1979 at 23:16:54 UTC, 10 km below the surface.

Map

Where it struck, with the other significant earthquakes within 200 km. Circles are sized and colored by magnitude; select one for its page.

The earthquake

Date
October 15, 1979
Time
23:16:54 UTC
Place
Mexicali, Imperial Valley, Mexico, California, United States
Magnitude
6.9 (Ms)
Focal depth
10 km (6 mi)
Intensity
9 on the Modified Mercalli scale
Tsunami
None recorded
Epicenter
32.634° N, 115.324° W

The toll

Injuries
91
Damage
$30 million
Houses destroyed
2
Houses damaged
1,565

Where the literature gives no number, NCEI records a description on a scale of 1 to 4, printed here in its words. Damage is in millions of US dollars of the year of the event, not adjusted for inflation.

What the record says

NCEI’s account, from the sources it cites.

1979. Oct. 15, 23 16 UTC. Imperial Valley area, on the Baja Calif., Mexico-California border. This major earthquake injured 91 people and caused an estimated $30 million in property damage in the Imperial Valley area. It destroyed two houses and 11 commercial buildings and damaged 1,565 houses and 440 commercial buildings. The most severe damage (MM intensity IX) was to the Imperial County Services building in El Centro, which had to be razed. The support pillars failed on this six-story reinforced concrete-frame structure, causing partial collapse of the east part of the building. It was designed under the 1967 provisions of the California Uniform Building Code. Other property damage caused by this earthquake at El Centro, Brawley, and Calexico and at Mexicali, Mexico, is typical of MM intensity VII, which is the highest intensity assigned to any location except the Imperial County Services building. (reference #542)

Photos

From the NCEI/WDS Natural Hazards Image Database (doi:10.7289/V5154F01). Only photos by the USGS and NOAA, which are public domain, are shown.

Imperial County Services Building Before and After 1979 Earthquake
Imperial County Services Building Before and After 1979 Earthquake Imperial County Services Building before (left) and after earthquake (right) showing support pillar failure at the east end of building. This 6-story reinforced concrete frame and shear wall structure completed in 1971 at a construction cost of $1.87 million, was designed to be earthquake resistant. However, during the quake the concrete at the base of the… Photo: Bay Area Regional Earthquake Preparedness Project, U.S. Geological Survey.
Sand Boil Near El Centro, 1979
Sand Boil Near El Centro, 1979 A sand boil near El Centro provides graphic evidence of liquefaction. Such boils were found especially along the southern extent of the Imperial Fault. Liquefaction occurs when earthquake ground shaking distorts the granular structure of the ground causing some loosely packed groups of grains to collapse together. Each collapse transfers pressure from the… Photo: G. Reagor, U.S. Geological Survey.
Merchandise on Floor
Merchandise on Floor Merchandise that fell from shelves in Brawley Drug Store. Aftershocks continued for several months, and several shocks were strong enough to knock merchandise from shelves and to break display windows in the area. Photo: G. Reagor, U.S. Geological Survey.
Fallen Porch
Fallen Porch Fallen porch on 200 block of G Street in Brawley. Several homes were damaged in this block. Most of the residential damage was to chimneys. Photo: G. Reagor, U.S. Geological Survey.
Support Pillar Failure, Imperial County Services Building, El Centro
Support Pillar Failure, Imperial County Services Building, El Centro The support pillar failed at the east end of the Imperial County Services Building in El Centro. This 6-story reinforced concrete frame and shear wall structure completed in 1971 at a construction cost of $1.87 million, was designed to be earthquake resistant. The concrete at the base of the columns was shattered and the vertical reinforced bars were… Photo: U.S. Geological Survey.
Offset of woodpile along Imperial fault
Offset of woodpile along Imperial fault Offset of woodpile shows right-lateral strike-slip offset of fault. The rupture occurred on the fault during the Imperial Valley, California, earthquake of 1979. Photo: G. Reagor, U.S. Geological Survey.
Offset of rows in plowed field
Offset of rows in plowed field A fault trace crosses a plowed field. The trace was produced by the October 1979 earthquake in the Imperial Valley. The agricultural industry suffered heavy losses from damage to canals, irrigation ditches, and subsurface drain tiles disturbed by the movement along the Imperial fault. Photo: G. Reagor, U.S. Geological Survey.
Imperial County Services Building
Imperial County Services Building View of the Imperial County Services Building after the 1979 El Centro (California) earthquake. Support framework is visible. This six-story reinforced concrete frame and shear wall structure was built in 1969 at a construction cost of $1.87 million, and was designed to be earthquake resistant. However, during the quake, the concrete at the base of the… Photo: G. Reagor, U.S. Geological Survey.

Other significant earthquakes nearby

Within 200 km, the deadliest first.

More

Significant earthquakes of 1979The 1900sEvery quake the USGS located in 1979Recent earthquakes near hereThis day in weather history

Sources

Significant earthquakes from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-09-24. NCEI earthquake 4847.