Калифорниядағы 7.1 балдық жер сілкінісі және оның себептері

Magnitude 7.1 earthquake in California
The earthquake caused minimal damage and no fatalities due to the distance of its epicenter from populated centers. The significance of this earthquake lies in the fact that, firstly, it had a relatively high magnitude but caused little damage and secondly, it offered more evidence that stress accumulation over time causes earthquakes.

It is thought that the 1999 Hector Mine earthquake may have been triggered by the 1992 Landers earthquake seven years prior, since the recurrence interval of large earthquakes in the Eastern California Shear Zone is considered to be in the order of thousands of years. That event had a magnitude of 7.3, similar to the Hector Mine quake, was also a strike slip event. Another reason why the Landers earthquake is likely to have triggered the Hector Mine earthquake as they both occurred 20 kilometers apart. The Hector Mine earthquake is thought to be an example of increased fault stress from a separate quake which built over seven years until finally rupturing in 1999. The largest of the twelve foreshocks had a magnitude of 3.8 and occurred at 7:41 PM PDT on the 15th of October.

This strike slip earthquake occurred in a remote part of the Mojave Desert, 47 mile (76 km) east southeast of Barstow, California, inside the Twentynine Palms Marine Corps Base. Strike slip faults are fractures where the blocks have mostly moved horizontally. If the block under the right foot of the observer straddling the fault moves towards the observer, the slip style is termed right lateral; if the block under the observer's left foot moves towards the observer, the fault is termed left lateral. This right lateral strike slip quake involved rupturing the Lavic Lake fault and the Bullion Fault. The earthquake was one of the strongest to occur during the last 100 years. The event was named after a nearby quarry in the Mojave Desert, located northwest of the epicenter. The earthquake was felt in much of Southern California as well as parts of Arizona and Nevada, including Las Vegas. Further, it awakened many people in Las Vegas with residents reporting dizziness and having trouble walking. The shaking from this seism was felt as far north as Carson City.

Almost no damage was reported in the immediate area of the earthquake due to the remote location of the epicenter in the Mojave Desert. The Marine Corps Air Ground Combat Center Twentynine Palms, located in the Mojave Desert, contained the surface rupture of the Hector Mine earthquake. The 1999 Hector Mine earthquake resulted in segments of aftershocks in the nearby area. The most notable of them, due to their large magnitudes, occurred several kilometers both north and south to the main shock. These aftershocks were measured to be of magnitude 5.9 and 5.7 The earthquake and its aftershocks resulted in surface deformation of several millimeters vertically and horizontally on many of the surrounding pre existing faults in the area. Again, due to the remote location of this earthquake's epicenter, no new precautions needed to be taken or implemented in the aftermath of the 1999 Hector Mine earthquake. However, this earthquake prompted further research into its precursor: the 1992 Landers earthquake which in the same area.