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Healdsburg Fault
The Healdsburg Fault is a seismically active geological feature associated with the Santa Rosa Plain and the Alexander Valley, in Sonoma County, California, United States. The eastern sides of these floodplains are bounded by strike-slip or transform faults. The maximum credible earthquake expected to be generated from the Healdsburg Fault is estimated to be about 7.5 on the Richter magnitude scale.C.Michael Hogan, John Torrey, Brian McElroy et al., ''Environmental Impact Report, Southeast Santa Rosa Annexation 2-88'', Earth Metrics Inc., Report 7941, California State Clearinghouse, Sacramento, Ca., March 1990 The last major event in Sonoma County were the 1969 Santa Rosa earthquakes, a magnitude 5.6 and 5.7 doublet that occurred on this fault. The county anticipates similar events every 20–30 years. The Rodgers Creek Fault passes through Sonoma Mountain and its north end terminates within Santa Rosa. The Healdsburg Fault continues along the east side of the Cotati Valle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Major California Faults And Ages Of Volcanics
Major ( commandant in certain jurisdictions) is a military rank of commissioned officer status, with corresponding ranks existing in many military forces throughout the world. When used unhyphenated and in conjunction with no other indicators, major is one rank above captain, and one rank below lieutenant colonel. It is considered the most junior of the field officer ranks. Background Majors are typically assigned as specialised executive or operations officers for battalion-sized units of 300 to 1,200 soldiers while in some nations, like Germany, majors are often in command of a company. When used in hyphenated or combined fashion, the term can also imply seniority at other levels of rank, including ''general-major'' or '' major general'', denoting a low-level general officer, and '' sergeant major'', denoting the most senior non-commissioned officer (NCO) of a military unit. The term ''major'' can also be used with a hyphen to denote the leader of a military band su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santa Rosa, California
Santa Rosa (Spanish language, Spanish for "Rose of Lima, Saint Rose") is a city and the county seat of Sonoma County, California, Sonoma County, in the North Bay (San Francisco Bay Area), North Bay region of the San Francisco Bay Area, Bay Area in California. Its estimated 2019 population was 178,127. It is the largest city in California's Wine Country and Redwood Empire, Redwood Coast. It is the fifth most populous city in the Bay Area after San Jose, California, San Jose, San Francisco, Oakland, California, Oakland, and Fremont, California, Fremont; and the List of largest California cities by population, 25th most populous city in California. History Early history Before the arrival of Europeans, what became known as the Santa Rosa Plain was occupied by a strong and populous tribe of Pomo natives known as the Bitakomtara. The Bitakomtara controlled the area closely, barring passage to others until permission was arranged. Those who entered without permission were subject t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Faults Of California
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. It also includes studies of earthquake environmental effects such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, glacial, fluvial, oceanic, atmospheric, and artificial processes such as explosions. A related field that uses geology to infer information regarding past earthquakes is paleoseismology. A recording of Earth motion as a function of time is called a seismogram. A seismologist is a scientist who does research in seismology. History Scholarly interest in earthquakes can be traced back to antiquity. Early speculations on the natural causes of earthquakes were included in the writings of Thales of Miletus (c. 585 BCE), Anaximenes of Miletus (c. 550 BCE), Aristotle (c. 340 BCE), and Zhan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taylor Mountain (Sonoma County, California)
Taylor Mountain is a summit at the northern extreme of the Sonoma Mountains in California. The mountain lies in the Laguna de Santa Rosa drainage basin; its east flank drains to Matanzas Creek, a northwestward flowing stream running the length of Bennett Valley, and its west flank drains to Five Creek. The mountain is named after California Gold Rush pioneer John Shackleford Taylor, who settled on the mountain slopes in 1853 to raise dairy cows and plant a vineyard.Clark Mason & Brett Wilkison ''Santa Rosa's new Taylor Mountain Regional Park opens to the public'' in '' The Press Democrat'' 24 February 2013 North of Taylor Mountain, Taylor Ridge descends toward the city of Santa Rosa. Some of Santa Rosa's urban expansion is taking place to the east of this ridge. Taylor Mountain is readily visible from Sonoma Mountain, Bennett Valley, the Santa Rosa Plain and from as far north as the Alexander Valley. The peak of Taylor Mountain defines (in part) the boundary between the So ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrabasic
Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed of usually greater than 90% mafic minerals (dark colored, high magnesium and iron content). The Earth's mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks. Intrusive ultramafic rocks Intrusive ultramafic rocks are often found in large, layered ultramafic intrusions where differentiated rock types often occur in layers. Such cumulate rock types do not represent the chemistry of the magma from which they crystallized. The ultramafic intrusives include the dunites, peridotites and pyroxenites. Other rare varieties include troctolite which has a greater perc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian reptiles, like the dinosaurs; an abundance of conifers and ferns; a hot Greenhouse and icehouse earth, greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of the three eras since Cambrian explosion, complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic. The era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth's history, and ended with the Cretaceous–Paleogene extinction event, another mass extinction whose victims included the non-avian dinosaurs, Pterosaur, pterosaurs, Mosasaur, mosasaurs, and Plesiosaur, plesiosaurs. The Mesozoic was a time of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russian River (California)
The Russian River (Southern Pomo: ''Ashokawna'', es, Río Ruso) is a southward-flowing river that drains of Sonoma and Mendocino counties in Northern California. With an annual average discharge of approximately 1,600,000 acre feet (2.0 km3), it is the second-largest river (after the Sacramento River) flowing through the nine-county Greater San Francisco Bay Area, with a mainstem long. Names The Southern Pomo know the river as Ashokawna (ʼaš:oʼkʰawna), "east water place" or "water to the east", and as Bidapte, "big river". Juan Rodríguez Cabrillo and his expedition may have travelled as far north as the Russian River in November 1542 before storms forced them to turn back south towards Monterey. The earliest Slavic name for the river, Slavyanka, appears on a Russian-American Company chart dated 1817. In 1827 the Spanish called it the San Ygnacio, and in 1843 the Spanish land grant referred to it as Rio Grande. The river takes its current name from Russian Iv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alluvial
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is typically geologically young and is not consolidated into solid rock. Sediments deposited underwater, in seas, estuaries, lakes, or ponds, are not described as alluvium. Floodplain alluvium can be highly fertile, and supported some of the earliest human civilizations. Definitions The present consensus is that "alluvium" refers to loose sediments of all types deposited by running water in floodplains or in alluvial fans or related landforms. However, the meaning of the term has varied considerably since it was first defined in the French dictionary of Antoine Furetière, posthumously published in 1690. Drawing upon concepts from Roman law, Furetière defined ''alluvion'' (the F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek grc, label=none, πλεῖστος, pleīstos, most and grc, label=none, καινός, kainós (latinized as ), 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the Isthmus of Panama, causing Great American Interchang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cotati, California
Cotati (; Miwok: ''Kota’ti'') is an incorporated city in Sonoma County, California, United States, located approximately north of San Francisco in the 101 corridor between Rohnert Park and Petaluma. Cotati's population as of the 2020 Census was 7,584, making it the smallest incorporated community in Sonoma County. Like all of Sonoma County, Cotati is included in both the San Francisco Bay Area and North Coast. Located in the Sonoma Coast AVA, Cotati can also be considered part of Wine Country. E & J Gallo Winery operates a vineyard called Two Rock Vineyard in the hills west of town. Cotati's hexagonal downtown plaza, one of only two hexagonal town layouts in the United States, is California Historical Landmark number 879. The other U.S. city with a hexagonal layout is Detroit, Michigan. History The Coast Miwok civilization thrived in the Cotati area since at least 2000 BC, with principal villages built near major streams. Documented villages in the area included ''Lume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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