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1948 Desert Hot Springs Earthquake
The 1948 Desert Hot Springs earthquake occurred on December 4 at 3:43 p.m. Pacific Standard Time with a moment magnitude of 6.4 and a maximum Mercalli intensity of VII (''Very strong''). The shock was felt from the central coast of California in the north, and to Baja California in the south, and came at a time when earthquake research in southern California resumed following the Second World War. It was one of two events in the 20th century that have occurred near a complex region of the southern San Andreas Fault system where it traverses the San Gorgonio Pass and the northern Coachella Valley. Damage was not severe, but some serious injuries occurred, and aftershocks continued until 1957. Preface The United States' involvement in World War II brought about a lapse in earthquake research in California, due to scientists and other technicians being assigned defense-related work, and the ongoing process of using earthquake records to establish their epicenters eventually ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault (geology)
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berkeley Seismological Laboratory
The Berkeley Seismological Laboratory (BSL) is a research lab at the Department of Geology at the University of California, Berkeley. It was created from the Berkeley Seismographic Stations, a site on the Berkeley campus where Worldwide Standard Seismographic Network instruments were first deployed in 1959. Today, BSL's mission is to "support fundamental research into all aspects of earthquakes, solid earth processes, and their effects on society". An experimental early warning system developed by BSL issued a warning 10 seconds before the 6.0 magnitude earthquake that hit the Napa region on August 24, 2014. Such a warning system could potentially give people time to take cover in the event of a quake, preventing injuries caused by falling debris, automatically stopping trains or shutting off gas lines. The system, developed in conjunction with the United States Geological Survey (USGS), the California Institute of Technology and the University of Washington, will eventually cove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strike And Dip
Strike and dip is a measurement convention used to describe the orientation, or attitude, of a planar geologic feature. A feature's strike is the azimuth of an imagined horizontal line across the plane, and its dip is the angle of inclination measured downward from horizontal. They are used together to measure and document a structure's characteristics for study or for use on a geologic map. A feature's orientation can also be represented by dip and dip direction, using the azimuth of the dip rather than the strike value. Linear features are similarly measured with trend and plunge, where "trend" is analogous to dip direction and "plunge" is the dip angle. Strike and dip are measured using a compass and a clinometer. A compass is used to measure the feature's strike by holding the compass horizontally against the feature. A clinometer measures the features dip by recording the inclination perpendicular to the strike. These can be done separately, or together using a tool such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismogram
A seismogram is a graph output by a seismograph. It is a record of the ground motion at a measuring station as a function of time. Seismograms typically record motions in three cartesian axes (x, y, and z), with the z axis perpendicular to the Earth's surface and the x- and y- axes parallel to the surface. The energy measured in a seismogram may result from an earthquake or from some other source, such as an explosion. Seismograms can record many things, and record many little waves, called microseisms. These tiny microseisms can be caused by heavy traffic near the seismograph, waves hitting a beach, the wind, and any number of other ordinary things that cause some shaking of the seismograph. Historically, seismograms were recorded on paper attached to rotating drums, a kind of chart recorder. Some used pens on ordinary paper, while others used light beams to expose photosensitive paper. Today, practically all seismograms are recorded digitally to make analysis by computer eas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern California
Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most populous urban agglomeration in the United States. The region generally contains ten of California's 58 counties: Imperial County, California, Imperial, Kern County, California, Kern, Los Angeles County, California, Los Angeles, Orange County, California, Orange, Riverside County, California, Riverside, San Bernardino County, California, San Bernardino, San Diego County, California, San Diego, Santa Barbara County, California, Santa Barbara, San Luis Obispo County, California, San Luis Obispo and Ventura County, California, Ventura counties. The Colorado Desert and the Colorado River are located on Southern California's eastern border with Arizona, and San Bernardino County shares a border with Nevada to the northeast. Southern California's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismometer
A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output of such a device—formerly recorded on paper (see picture) or film, now recorded and processed digitally—is a seismogram. Such data is used to locate and characterize earthquakes, and to study the Earth's internal structure. Basic principles A simple seismometer, sensitive to up-down motions of the Earth, is like a weight hanging from a spring, both suspended from a frame that moves along with any motion detected. The relative motion between the weight (called the mass) and the frame provides a measurement of the vertical ground motion. A rotating drum is attached to the frame and a pen is attached to the weight, thus recording any ground motion in a seismogram. Any movement from the ground moves the frame. The mass tends not to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge University Press
Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press A university press is an academic publishing house specializing in monographs and scholarly journals. Most are nonprofit organizations and an integral component of a large research university. They publish work that has been reviewed by schola ... in the world. It is also the King's Printer. Cambridge University Press is a department of the University of Cambridge and is both an academic and educational publisher. It became part of Cambridge University Press & Assessment, following a merger with Cambridge Assessment in 2021. With a global sales presence, publishing hubs, and offices in more than 40 Country, countries, it publishes over 50,000 titles by authors from over 100 countries. Its publishing includes more than 380 academic journals, monographs, reference works, school and uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cajon Pass
Cajon Pass (; Spanish: ''Puerto del Cajón'' or ''Paso del Cajón'') is a mountain pass between the San Bernardino Mountains to the east and the San Gabriel Mountains to the west in Southern California. Created by the movements of the San Andreas Fault, it has an elevation of . Located in the Mojave Desert, the pass is an important link from the Greater San Bernardino Area to the Victor Valley, and northeast to Las Vegas. The Cajon Pass area is on the Pacific Crest Trail. Cajon Pass is at the head of Horsethief Canyon, traversed by California State Route 138 (SR 138) and railroad tracks owned by BNSF Railway and Union Pacific Railroad. Improvements in 1972 reduced the railroad's maximum elevation from about while reducing curvature. Interstate 15 does not traverse Cajon Pass, but rather the nearby Cajon Summit, , elevation . The entire area, Cajon Pass and Cajon Summit, is often referred to as Cajon Pass, but a distinction is made between Cajon Pass and Cajon Summit. In 1851 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Rupture
In seismology, surface rupture (or ground rupture, or ground displacement) is the visible offset of the ground surface when an earthquake rupture along a fault affects the Earth's surface. Surface rupture is opposed by buried rupture, where there is no displacement at ground level. This is a major risk to any structure that is built across a fault zone that may be active, in addition to any risk from ground shaking. Surface rupture entails vertical or horizontal movement, on either side of a ruptured fault. Surface rupture can affect large areas of land. __TOC__ Lack of surface rupture Not every earthquake results in surface rupture, particularly for smaller and deeper earthquakes. In some cases, however, the lack of surface effects is because the fault that moved does not reach the surface. For example, the 1994 Northridge earthquake had a moment magnitude of 6.7, caused major damage in the Los Angeles area, occurred at below the Earth's surface, but did not cause surface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1986 North Palm Springs Earthquake
The 1986 North Palm Springs earthquake occurred on July 8 at with a moment magnitude of 6.0 and a maximum Mercalli Intensity of VII (''Very strong''). The shock occurred in a complex setting along the San Andreas Fault Zone where it bisects San Gorgonio Mountain and San Jacinto Peak at the San Gorgonio Pass and was the first in a series of three earthquakes that affected southern California and the northern Owens Valley in July 1986. Numerous strong motion instruments recorded the event, one of which showed relatively high accelerations. Between 29 and 40 people were injured, and financial losses were estimated to be in the range of $4.5–6 million. Preface July 1986 was an unusually active month for moderate to strong earthquakes in California, with three events occurring in less than two weeks. Each had mild to moderate effects and began on July 8 with the event near Palm Springs. The second event was a 5.8 shock that occurred off the coast of Oceanside on July 13. Whil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Gorgonio Mountain
San Gorgonio Mountain, also known locally as Mount San Gorgonio, or Old Greyback, is the highest peak in Southern California and the Transverse Ranges at . It is in the San Bernardino Mountains, east of the city of San Bernardino and north-northeast of San Gorgonio Pass. It lies within the San Gorgonio Wilderness, part of the Sand to Snow National Monument managed by the San Bernardino National Forest. Spanish missionaries in the area during the early 17th century named the peak after Saint Gorgonius. Since it is the highest point in a region which is separated from higher peaks (e.g. in the Sierra Nevada) by relatively low terrain, San Gorgonio Mountain is one of the most topographically prominent peaks in the United States. It is ranked 7th among peaks in the 48 contiguous states and 18th overall. Like other high peaks in the Transverse Ranges, the mountain has a pyramid shape, with a steep north face and a slightly shallower south face. The mountain is large and broad; th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1992 Landers Earthquake
The 1992 Landers earthquake occurred on Sunday, June 28 with an epicenter near the town of Landers, California, Landers, California, in San Bernardino County. The shock had a Moment magnitude scale, moment magnitude of 7.3 and a maximum Mercalli intensity scale, Mercalli intensity of IX (''Violent''). Earthquake At 4:57 a.m. local time (11:57 UTC) on June 28, 1992, a Moment magnitude scale, magnitude 7.3 earthquake awoke much of Southern California. Though it turned out it was not the so-called "The Big One (earthquake), Big One" as many people would think, it was still a very strong earthquake. The shaking lasted for two to three minutes. Although this earthquake was much more powerful than the 1994 Northridge earthquake, the damage and loss of life were minimized by its location in the sparsely-populated Mojave Desert. The earthquake was a Sinistral and dextral, right-lateral strike-slip event, and involved the rupture of several different Fault (geology), faults over a l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
