The San Andreas Fault is a continental right-lateral strike-slip transform fault that extends roughly 1,200 kilometers (750 mi) through the Californias. It forms the tectonic boundary between the Pacific Plate and the North American Plate. Traditionally, for scientific purposes, the fault has been classified into three main segments, each with different characteristics and a different degree of earthquake risk. The average slip rate along the entire fault ranges from 20 to 35 mm per year.
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.
Pyramid Lake is the geographic sink of the basin of the Truckee River, 40 mi (64 km) northeast of Reno, Nevada, United States.
Lake Lahontan was a large endorheic Pleistocene lake of modern northwestern Nevada that extended into northeastern California and southern Oregon. The area of the former lake is a large portion of the Great Basin that borders the Sacramento River watershed to the west.
The Truckee River is a river in the U.S. states of California and Nevada. The river flows northeasterly and is 121 miles (195 km) long. The Truckee is the sole outlet of Lake Tahoe and drains part of the high Sierra Nevada, emptying into Pyramid Lake in the Great Basin. Its waters are an important source of irrigation along its valley and adjacent valleys.
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 Sevier orogeny was a mountain-building event that affected western North America from northern Canada to the north to Mexico to the south.
The Walker Lane is a geologic trough roughly aligned with the California/Nevada border southward to where Death Valley intersects the Garlock Fault, a major left lateral, or sinistral, strike-slip fault. The north-northwest end of the Walker Lane is between Pyramid Lake in Nevada and California's Lassen Peak where the Honey Lake Fault Zone, the Warm Springs Valley Fault, and the Pyramid Lake Fault Zone meet the transverse tectonic zone forming the southern boundary of the Modoc Plateau and Columbia Plateau provinces. The Walker Lane takes up 15 to 25 percent of the boundary motion between the Pacific Plate and the North American Plate, the other 75 percent being taken up by the San Andreas Fault system to the west. The Walker Lane may represent an incipient major transform fault zone which could replace the San Andreas as the plate boundary in the future.
The Kern Canyon Fault is a dextral strike-slip fault (horizontal) that runs roughly around 150 km (93 mi) beside the Kern River Canyon through the mountainous area of the Southern Sierra Nevada Batholith. The fault was a reverse fault in the Early Cretaceous epoch during the primal stages of the Farallon Plate subduction beneath the North American Continental Plate and fully transitioned into a strike-slip shear zone during the Late Cretaceous.
The Furnace Creek Fault Zone (FCFZ) is a geological fault that is located in Eastern California and southwestern Nevada. The right lateral-moving (dextral) fault extends for some 200 km (120 mi) between a connection with the Death Valley Fault Zone in the Amargosa Valley and northward to a termination in the Fish Lake Valley of southwest Nevada. The northern segment of the FCFZ is also referred to as the Fish Lake Valley Fault Zone. The FCFZ is considered an integral part of the Walker Lane.
The Honey Lake Fault Zone is a right lateral-moving (dextral) geologic fault extending through northwestern Nevada and northeastern California. It is considered an integral part of the Walker Lane.
The Olympic-Wallowa lineament (OWL) – first reported by cartographer Erwin Raisz in 1945 on a relief map of the continental United States – is a physiographic feature of unknown origin in the state of Washington running approximately from the town of Port Angeles, on the Olympic Peninsula to the Wallowa Mountains of eastern Oregon.
The Brothers Fault Zone (BFZ) is the most notable of a set of northwest-trending fault zones including the Eugene–Denio, McLoughlin, and Vale zones that dominate the geological structure of most of Oregon. These are also representative of a regional pattern of generally northwest-striking geological features ranging from Walker Lane on the California–Nevada border to the Olympic–Wallowa Lineament in Washington; these are generally associated with the regional extension and faulting of the Basin and Range Province, of which the BFZ is considered the northern boundary.
Lake Panamint is a former lake that occupied Panamint Valley in California during the Pleistocene. It was formed mainly by water overflowing through the Owens River and which passed through Lake Searles into the Panamint Valley. At times, Lake Panamint itself overflowed into Death Valley and Lake Manly.
The 2019 Ridgecrest earthquakes of July 4 and 5 occurred north and northeast of the town of Ridgecrest, California located in Kern County and west of Searles Valley. They included three initial main shocks of 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 Thursday, 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 Friday, 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 1934 Hansel Valley earthquake occurred on March 12 at approximately 8:05 a.m. MST with a moment magnitude of 6.6 and a maximum Mercalli intensity of VIII (Severe). The shock originated in the Hansel Valley at the north end of the Great Salt Lake in Utah in the United States. Damage was mostly confined to vulnerable buildings, and two people died. The dip-slip (normal) fault that generated the shock ruptured the surface of the ground and other geologic features were documented. A large aftershock occurred three hours after the initial event and may have caused additional damage.
In 1954, the state of Nevada was struck by a series of earthquakes that began with three magnitude 6.0+ events in July and August that preceded the Mw 7.1–7.3 mainshock and M 6.9 aftershock, both on December 12. All five earthquakes are among 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.
The Cedar Mountain earthquake of 1932 was one of the largest seismic events in the US state of Nevada. The 7.3 earthquake struck at Cedar Mountain in Western Nevada. Shaking was felt as far as Oregon, Southern California, and the Rocky Mountains area. Nevada is the third most seismically active state in the United States due to ongoing rifting occurring within the North American Plate. Extension or thinning of the crust has resulted in numerous faults accommodating strain, at the same time, producing earthquakes. Since the earthquake occurred in a remote part of the state, damage was limited and no deaths were reported.
