The Independence Valley fault system is a group of interrelated normal faults located in northeastern Nevada in the United States. The fault system is characteristic of faulting throughout the Great Basin region.
The Independence Valley fault system is a group of interrelated normal faults located in northeastern Nevada in the United States. The fault system is characteristic of faulting throughout the Great Basin region.
California is a U.S. state on the western coast of North America. Covering an area of 163,696 sq mi (423,970 km2), California is among the most geographically diverse states. The Sierra Nevada, the fertile farmlands of the Central Valley, and the arid Mojave Desert of the south are some of the major geographic features of this U.S. state. It is home to some of the world's most exceptional trees: the tallest, most massive, and oldest. It is also home to both the highest and lowest points in the 48 contiguous states. The state is generally divided into Northern and Southern California, although the boundary between the two is not well defined. San Francisco is decidedly a Northern California city and Los Angeles likewise a Southern California one, but areas in between do not often share their confidence in geographic identity. The US Geological Survey defines the geographic center of the state at a point near North Fork, California.
The San Andreas Fault is a continental transform fault that extends roughly 1,200 kilometers (750 mi) through California. It forms the tectonic boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip (horizontal). The fault divides into three segments, each with different characteristics and a different degree of earthquake risk. The slip rate along the fault ranges from 20 to 35 mm /yr.
The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating between narrow faulted mountain chains and flat arid valleys or basins. The physiography of the province is the result of tectonic extension that began around 17 million years ago in the early Miocene epoch.
Owens Valley is an arid valley of the Owens River in eastern California in the United States. It is located to the east of the Sierra Nevada, west of the White Mountains and Inyo Mountains, and north of the Mojave Desert. It sits on the west edge of the Great Basin. The mountain peaks on the West side reach above 14,000 feet (4,300 m) in elevation, while the floor of the Owens Valley is about 4,000 feet (1,200 m), making the valley the deepest in the United States. The Sierra Nevada casts the valley in a rain shadow, which makes Owens Valley "the Land of Little Rain." The bed of Owens Lake, now a predominantly dry endorheic alkali flat, sits on the southern end of the valley.
The 1872 Owens Valley earthquake – also known as the Lone Pine earthquake – struck on March 26 at 02:30 local time in the Owens Valley, with the epicenter near the town of Lone Pine. Its magnitude has been estimated at Mw 7.4 to 7.9, with a maximum Mercalli Intensity of X (Extreme). It was one of the largest earthquakes to hit California in recorded history and was similar in size to the 1906 San Francisco earthquake. Twenty-seven people were killed and fifty-six were injured.
The exposed geology of the Yosemite area includes primarily granitic rocks with some older metamorphic rock. The first rocks were laid down in Precambrian times, when the area around Yosemite National Park was on the edge of a very young North American continent. The sediment that formed the area first settled in the waters of a shallow sea, and compressive forces from a subduction zone in the mid-Paleozoic fused the seabed rocks and sediments, appending them to the continent. Heat generated from the subduction created island arcs of volcanoes that were also thrust into the area of the park. In time, the igneous and sedimentary rocks of the area were later heavily metamorphosed.
The Kern River, originally Rio de San Felipe, later La Porciuncula, is a river in the U.S. state of California, approximately 165 miles (270 km) long. It drains an area of the southern Sierra Nevada mountains northeast of Bakersfield. Fed by snowmelt near Mount Whitney, the river passes through scenic canyons in the mountains and is a popular destination for whitewater rafting and kayaking. It is the southernmost major river system in the Sierra Nevada, and is the only major river in the Sierra that drains in a southerly direction.
The Pah Rah Range is a mountain range located in western Nevada in Washoe County just to the northeast of Reno. It is a hook shaped range with the main eastern portion oriented northwest-southeast, approximately 20 miles (32 km) long. The northwest flowing Cottonwood Creek in Warm Springs Valley is bounded on three sides by the range. To the south and east the Truckee River forms the boundary and Pyramid Lake is at the northeast. Spanish Springs Valley north of Reno forms the southwest margin. To the north the narrow Mullen Pass separates the Pah Rah Range from the Virginia Mountains.
The exposed geology of the Death Valley area presents a diverse and complex set of at least 23 formations of sedimentary units, two major gaps in the geologic record called unconformities, and at least one distinct set of related formations geologists call a group. The oldest rocks in the area that now includes Death Valley National Park are extensively metamorphosed by intense heat and pressure and are at least 1700 million years old. These rocks were intruded by a mass of granite 1400 Ma and later uplifted and exposed to nearly 500 million years of erosion.
The Virginia Mountains is an irregular mountain range entirely in Washoe County, Nevada, that generally extends north-northwest to south-southeast for 22 miles (35 km).
The Delamar Mountains are a mountain range in Lincoln County, Nevada, named after Captain Joseph Raphael De Lamar. The range extends for approximately 50 miles (80 km) in a NNE–SSW orientation with a width of about 11 miles (18 km). Surrounding ranges include the Burnt Springs Range and the Chief Range to the north, the Clover Mountains and Meadow Valley Mountains to the east and the Sheep Range and South Pahroc Range on the west. The Delamar Valley lies to the west, the Kane Springs Valley to the east and the Coyote Springs Valley lies to the south of the range.
The Pyramid Lake Fault Zone is an active right lateral-moving (dextral) geologic fault located in western Nevada. It is considered an integral part of the Walker Lane.
The 1915 Pleasant Valley earthquake occurred at 22:53:21 on October 2 in north-central Nevada. With a moment magnitude of 6.8 and a maximum Mercalli intensity of X (Extreme), it was the strongest earthquake ever recorded in the state.
The Tobin Range is a mountain range in eastern Pershing County, Nevada. The linear range is typical of the basin and range structure with an approximate length and width of 32.5 miles (52.3 km) by 6 miles (9.7 km) with a NNE orientation. The Tobin Range includes Mount Tobin, a 9,754 feet (2,973 m) summit that dominates the surrounding area. Mount Tobin has a latitude of 40°22′37″N and a longitude of 117°31′33″W.
The 1986 Chalfant Valley earthquake struck southern Mono County near Bishop and Chalfant, California at 07:42:28 Pacific Daylight Time on July 21. With a moment magnitude of 6.2 and a maximum Mercalli intensity of VI (Strong), the shock injured two people and caused property damage estimated at $2.7 million in the affected areas. There was a significant foreshock and aftershock sequence that included a few moderate events, and was the last in a series of three earthquakes that affected southern California and the northern Owens Valley in July 1986.
The 1838 San Andreas earthquake is believed to be a rupture along the northern part of the San Andreas Fault in June 1838. It affected approximately 100 km of the fault, from the San Francisco Peninsula to the Santa Cruz Mountains. It was a strong earthquake, with an estimated moment magnitude of 6.8 to 7.2, making it one of the largest known earthquakes in California. The region was lightly populated at the time, although structural damage was reported in San Francisco, Oakland, and Monterey. It is unknown whether there were fatalities. Based on geological sampling, the fault created approximately 1.5 meters of slip.
The 2019 Ridgecrest earthquakes of July 4 and 5 occurred north and northeast of the town of Ridgecrest, California and west of Searles Valley. They included three initial main shocks of Mw magnitudes 6.4, 5.4, and 7.1, and many perceptible aftershocks, mainly within the area of the Naval Air Weapons Station China Lake. Eleven months later, a Mw 5.5 aftershock took place to the east of Ridgecrest. The first main shock occurred on July 4 at 10:33 a.m. PDT, approximately 18 km (11.2 mi) ENE of Ridgecrest, and 13 km (8.1 mi) WSW of Trona, on a previously unnoticed NE-SW trending fault where it intersects the NW-SE trending Little Lake Fault Zone. This quake was preceded by several smaller earthquakes, and was followed by more than 1,400 detected aftershocks. The M 5.4 and M 7.1 quakes struck on July 5 at 4:08 a.m. and 8:19 p.m. PDT approximately 10 km (6 miles) to the northwest. The latter, now considered the mainshock, was the most powerful earthquake to occur in the state in 20 years. Subsequent aftershocks extended approximately 50 km (~30 miles) along the Little Lake Fault Zone.
On May 15, 2020 at 4:03:27 local time, a magnitude 6.5 earthquake struck ~35 miles (56 km) west of Tonopah, Nevada in the Monte Cristo Range near the California-Nevada border. It was Nevada's largest earthquake in 66 years.
The 2008 Wells earthquake occurred at 07:16:02 on February 21, 2008 just northeast of the town of Wells, Nevada, causing moderate damage, mainly to older brick buildings. The quake was centered on one of the faults of the Independence Valley fault system, about nine kilometers beneath the surface and had no known near-surface offset.
In 1954, the state of Nevada was struck by a series of earthquakes that began with several M 6.0s in July and August that preceded the M 7.3 main shock, and an M 6.9 on December 12. All five earthquakes remain some of the largest in the state, and the largest since the Cedar Mountain earthquake of 1932 and Pleasant Valley event in 1915. The earthquake was felt throughout much of the western United States.
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