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1898 Mare Island Earthquake
The 1898 Mare Island earthquake occurred in Northern California on with a moment magnitude of 5.8–6.4 and a maximum Mercalli intensity of VIII–IX (''Severe''–''Violent''). Its area of perceptibility included much of northern and central California and western Nevada. Damage amounted to $350,000 (about $10,700,000 inflation adjusted to 2018) and was most pronounced on Mare Island, a peninsula in northern San Francisco Bay. While relatively strong effects there were attributed to vulnerable buildings, moderate effects elsewhere in the San Francisco Bay Area consisted of damaged or partially collapsed structures, and there were media reports of a small tsunami and mostly mild aftershocks that followed. The mechanism of the shock is unknown, but several independent investigations focused on different aspects to gain a better understanding of the intensity, magnitude, source fault, and epicenter of this pre-instrumental event. Most investigators placed it under or to the no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moment Magnitude Scale
The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 paper by Thomas C. Hanks and Hiroo Kanamori. Similar to the local magnitude/Richter scale () defined by Charles Francis Richter in 1935, it uses a logarithmic scale; small earthquakes have approximately the same magnitudes on both scales. Despite the difference, news media often says "Richter scale" when referring to the moment magnitude scale. Moment magnitude () is considered the authoritative magnitude scale for ranking earthquakes by size. It is more directly related to the energy of an earthquake than other scales, and does not saturate—that is, it does not underestimate magnitudes as other scales do in certain conditions. It has become the standard scale used by seismological authorities like the U.S. Geological SurveyThe "USGS Ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mendocino Fracture Zone
The Mendocino Fracture Zone is a fracture zone and transform boundary over 4000 km (2500 miles) long, starting off the coast of Cape Mendocino in far northern California. It runs westward from a triple junction with the San Andreas Fault and the Cascadia subduction zone to the southern end of the Gorda Ridge. It continues on west of its junction with the Gorda Ridge, as an inactive remnant section which extends for several hundred miles. Technically, a fracture zone is not a transform fault, but in the case of the Mendocino, the term has been loosely applied to the active fault segment east of the Gorda Ridge as well as to the true fracture zone segment west of it. Many seismologists refer to the active segment as the Mendocino Fault or Mendocino fault zone. The fault section demarcates the boundary between the northwestward-moving Pacific Plate and the eastward-moving Gorda Plate. The Gorda Plate is subducting beneath the North American Plate just offshore of Cape ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1969 Santa Rosa Earthquakes
At 04:56 and 06:19 UTC on October 2, 1969 (21:56 and 23:19 PDT October 1), a pair of earthquakes of magnitude 5.6 and 5.7, respectively, struck the city of Santa Rosa, California, killing one person and damaging buildings. The maximum felt intensity for the two events was VII (''Very strong'') and VIII (''Severe'') respectively on the Mercalli intensity scale. The $8.35 million cost of the earthquakes went mostly to replace buildings damaged beyond repair. There were at least 200 aftershocks after the initial pair of earthquakes. At the time they were the largest earthquakes to affect the northern San Francisco Bay Area since the 1906 San Francisco earthquake. Tectonic setting The current tectonics of northern California are mainly controlled by the San Andreas Fault system, the zone of dextral strike-slip faulting that accommodates displacement between the North American Plate and the Pacific Plate along this transform boundary. In addition to the San Andreas Fault itself t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoseismal Map
In seismology, an isoseismal map is used to show lines of equally felt seismic intensity, generally measured on the Modified Mercalli scale. Such maps help to identify earthquake epicenters, particularly where no instrumental records exist, such as for historical earthquakes. They also contain important information on ground conditions at particular locations, the underlying geology, radiation pattern of the seismic waves, and the response of different types of buildings. They form an important part of the macroseismic approach, i.e. that part of seismology dealing with noninstrumental data. The shape and size of the isoseismal regions can be used to help determine the magnitude, focal depth, and focal mechanism of an earthquake. History The first known isoseismal map was produced for the 1810 earthquake in Mór in Hungary, and published by Kitaibel and Tomtsányi in 1814. The first, six-level intensity scale was proposed by Egen in 1828 for an earthquake in Rhineland. Rober ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carson City, Nevada
Carson City is an independent city and the capital of the U.S. state of Nevada. As of the 2020 census, the population was 58,639, making it the sixth largest city in Nevada. The majority of the city's population lives in Eagle Valley, on the eastern edge of the Carson Range, a branch of the Sierra Nevada, about south of Reno. The city is named after the mountain man Kit Carson. The town began as a stopover for California-bound immigrants, but developed into a city with the Comstock Lode, a silver strike in the mountains to the northeast. The city has served as Nevada's capital since statehood in 1864; for much of its history it was a hub for the Virginia and Truckee Railroad, although the tracks were removed in 1950. Before 1969, Carson City was the county seat of Ormsby County. That year the state legislature abolished the county and included its territory into a revised city charter for a Consolidated Municipality of Carson City. With the consolidation, the city limi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chico, California
Chico ( ; Spanish for "little") is the most populous city in Butte County, California. Located in the Sacramento Valley region of Northern California, the city had a population of 101,475 in the 2020 census, reflecting an increase from 86,187 in the 2010 Census. Chico is the cultural and economic center of the northern Sacramento Valley, as well as the largest city in California north of the capital city of Sacramento. The city is known as a college town, as the home of California State University, Chico, and for Bidwell Park, one of the largest urban parks in the world. History The first known inhabitants of the area now known as Chico—a Spanish word meaning "little"—were the Mechoopda Maidu Native Americans. The City of Chico was founded in 1860 by John Bidwell, a member of one of the first wagon trains to reach California in 1843. During the American Civil War, Camp Bidwell (named for John Bidwell, by then a brigadier general of the California Militia), wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USGS – Green Valley Fault
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredth anniversa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredth an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Of California Rift Zone
The Gulf of California Rift Zone (GCRZ) is the northernmost extension of the East Pacific Rise which extends some from the mouth of the Gulf of California to the southern terminus of the San Andreas Fault at the Salton Sink. The GCRZ is an incipient rift zone akin to the Red Sea Rift. In the GCRZ continental crust originally associated with the North American Plate has been pulled apart by tectonic forces and is being replaced by newly formed oceanic crust and seafloor spreading. The rifting has resulted in the transfer of the Baja California Peninsula to the Pacific Plate. List of GCRZ transform faults From north to south: * Imperial Fault Zone * Cerro Prieto Fault * Ballenas Fault * Partida Fault * San Lorenzo Fault * Guaymas Fault * Carmen Fault * Farallon Fault * Atl Fault * Pescadero Fault * Tamayo Fault List of GCRZ rift basins From north to south: * Brawley Seismic Zone * Cerro Prieto * Wagner Basin * Consag Basin * Adair-Tepoca Basin * Tiburon Basin * Delfin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
