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Joshua Tree National Park Geology

Hector Mine Earthquake Summary

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Map showing
Click on image to enlarge to full size. Map from U.S. Geological Survey Pasadena Office of Earthquake Information

spacer image A magnitude 7.1 earthquake rocked the Joshua Tree National Park region at 2:46 a.m. local time Saturday, October 16, 1999. The event was located in the Mojave desert, about 47 miles east-southeast of Barstow and 32 miles north of Joshua Tree.
spacer image On average, an earthquake of magnitude 7.0 is expected to generate about four aftershocks of magnitude 5 or larger within the next week. 25 aftershocks of magnitude 4.0 or larger occurred within 36 hours of the main shock.
spacer image The earthquake occurred on the Lavic Lake fault, which slices in a north-northwest direction through the eastern Mojave shear zone. Scientists have identified a 40-kilometer long surface rupture within the Twenty Nine Palms Marine Base. So far, a maximum offset of 3.8 - 4.7 meters was measured.
spacer image The map below shows the location of Hector Mine earthquake as well as the epicenters of events assocated with the 1992 Joshua Trea-Landers earthquake sequence. Small stars show locations of Hector Mine aftershocks with a magnitude 4 or larger (as of noon on 10/19/99).
spacer image (Updated 8:47 a.m., 10/19/99)

Hector Mine Earthquake and related links

pebbleHector Mine earthquake summary
pebbleShaded Relief Map: Hector Mine earthquake (10/19/99)
- 130 MB image
pebbleHector Mine EQ ground-shaking intensity maps
pebbleHector Mine EQ damage reports and more
pebbleMap of seismograph network in the Joshua Tree region
pebbleU.S. Geological Survey Earthquake Information
pebbleAlmost real-time map of California’s recent earthquakes
pebbleGround motion map of Hector Mine main shock
pebbleGround motion maps Hector Mine aftershocks
pebbleSeismo-links Exhaustive link list!
pebbleAll About Earthquakes
- Earthquake intensity
- Earthquake magnitude
- Faults
- Earthquake epicenter and focus
- See Sunset Crater’s seismograph

| U.S. Geological Survey Pasadena Office of Earthquake Information |
| Joshua Tree earthquake home | Joshua Tree National Park home |
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This page was last updated on 10/19/99
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