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Tsunami Warning System
A tsunami warning system (TWS) is used to detect tsunamis in advance and issue the warnings to prevent loss of life and damage to property. It is made up of two equally important components: a network of sensors to detect tsunamis and a communications infrastructure to issue timely alarms to permit evacuation of the coastal areas. There are two distinct types of tsunami warning systems: international and regional. When operating, seismic alerts are used to instigate the watches and warnings; then, data from observed sea level height (either shore-based tide gauges or DART buoys) are used to verify the existence of a tsunami. Other systems have been proposed to augment the warning procedures; for example, it has been suggested that the duration and frequency content of t-wave energy (which is earthquake energy trapped in the ocean SOFAR channel) is indicative of an earthquake's tsunami potential. History and forecasting The first rudimentary system to alert communities of an i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tsunami Evac Sign Seaside Oregon
A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a tsunamis in lakes, large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, landslides, Ice calving, glacier calvings, impact event, meteorite impacts and other disturbances) above or below water all have the potential to generate a tsunami. Unlike normal Wind wave, ocean waves, which are generated by wind, or tides, which are in turn generated by the gravitational pull of the Moon and the Sun, a tsunami is generated by the displacement of water from a large event. Tsunami waves do not resemble normal undersea currents or Wind wave, sea waves because their Wind wave#Formation, wavelength is far longer. Rather than appearing as a breaking wave, a tsunami may instead initially resemble a rapidly rising tide. For this reason, it is often referred to as a tidal wave, although this usage is not favoured ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palmer, Alaska
Palmer is a city in and the county seat, borough seat of the Matanuska-Susitna Borough, Alaska, United States, located northeast of Anchorage on the Glenn Highway in the Matanuska-Susitna Valley, Matanuska Valley. It is the List of cities in Alaska, ninth-largest city in Alaska, and forms part of the Anchorage, Alaska, Anchorage Anchorage metropolitan area, Metropolitan Statistical Area. As of the 2020 United States census, 2020 census, the population of the city is 5,888, down from 5,937 in 2010. Palmer hosts the annual Alaska State Fair, and is also the headquarters of the National Tsunami Warning Center. History The city was named after George Palmer, a trader. In the late 19th century, the U.S. government began to take interest in the Matanuska coal fields located north of Palmer. This interest sparked financiers to consider constructing the Alaska Railroad, Alaska Central Railroad in 1904. The advent of World War I created a need for high-quality coal to fuel U.S. ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Period Of A Function
A periodic function, also called a periodic waveform (or simply periodic wave), is a function that repeats its values at regular intervals or periods. The repeatable part of the function or waveform is called a ''cycle''. For example, the trigonometric functions, which repeat at intervals of 2\pi radians, are periodic functions. Periodic functions are used throughout science to describe oscillations, waves, and other phenomena that exhibit periodicity. Any function that is not periodic is called ''aperiodic''. Definition A function is said to be periodic if, for some nonzero constant , it is the case that :f(x+P) = f(x) for all values of in the domain. A nonzero constant for which this is the case is called a period of the function. If there exists a least positive constant with this property, it is called the fundamental period (also primitive period, basic period, or prime period.) Often, "the" period of a function is used to mean its fundamental period. A function ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrographic And Oceanographic Service Of The Chilean Navy
SHOA or Servicio Hidrográfico y Oceanográfico de la Armada de Chile (Spanish for Hydrographic and Oceanographic Service of the Chilean Navy) is an agency of the Chilean Navy managing situations dealing with hydrography and oceanography, including tides and tsunamis. SHOA has faced severe criticism after the 2010 Chile earthquake, the largest earthquake since the 1960 Valdivia earthquake. Criticism include the lack of coordination with other authorities and the ONEMI (Chile's emergency office). ONEMI, SHOA and the government have been accused of the initial neglect of the tsunami warning sent by the Pacific Tsunami Warning Center which resulted in the deaths of hundred of persons. The director of SHOA Mariano Rojas was removed from office and replaced by Patricio Carrasco due to his responsibility over the failed tsunami warning. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tide Gauge
A tide gauge is a device for measuring the change in sea level relative to a vertical datum. It is also known as a mareograph, marigraph, and sea-level recorder. When applied to freshwater continental water body, water bodies, the instrument may also be called a limnimeter. Operation Sensors continuously record the height of the water level with respect to a height reference surface close to the geoid. Water enters the device by the bottom pipe (far end of the tube, see picture), and electronic sensors measure its height and send the data to a tiny computer. Historical data are available for about 1,450 stations worldwide, of which about 950 have provided updates to the global data center since January 2010. At some places records cover centuries, for example in Amsterdam where data dating back to 1700 is available. When it comes to estimating the greater ocean picture, new modern tide gauges can often be improved upon by using satellite data. Tide gauges are used to measure t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tilt-Sensor
An inclinometer or clinometer is an instrument used for measuring angles of slope, elevation, or depression of an object with respect to gravity's direction. It is also known as a ''tilt indicator'', ''tilt sensor'', ''tilt meter'', ''slope alert'', ''slope gauge'', ''gradient meter'', ''gradiometer'', ''level gauge'', ''level meter'', ''declinometer'', and ''pitch & roll indicator''. Clinometers measure both inclines and declines using three different units of measure: degrees, percentage points, and topos. The astrolabe is an example of an inclinometer that was used for celestial navigation and location of astronomical objects from ancient times to the Renaissance. A ''tilt sensor'' can measure the tilting in often two axes of a reference plane in two axes. In contrast, a full motion would use at least three axes and often additional sensors. One way to measure tilt angle with reference to the earth's ground plane, is to use an accelerometer. Typical applications can be fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antenna (radio)
In radio-frequency engineering, an antenna (American English) or aerial (British English) is an electronic device that converts an alternating current, alternating electric current into radio waves (transmitting), or radio waves into an electric current (receiving). It is the interface between radio waves Radio propagation, propagating through space and electric currents moving in metal Electrical conductor, conductors, used with a transmitter or receiver (radio), receiver. In transmission (telecommunications), transmission, a radio transmitter supplies an electric current to the antenna's Terminal (electronics), terminals, and the antenna radiates the energy from the current as electromagnetic radiation, electromagnetic waves (radio waves). In receiver (radio), reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be amplifier, amplified. Antennas are essential components ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Positioning System
The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephone or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls, and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. Overview The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was launched in 1978 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accelerometer
An accelerometer is a device that measures the proper acceleration of an object. Proper acceleration is the acceleration (the rate of change (mathematics), rate of change of velocity) of the object relative to an observer who is in free fall (that is, relative to an inertial frame of reference). Proper acceleration is different from coordinate acceleration, which is acceleration with respect to a given coordinate system, which may or may not be accelerating. For example, an accelerometer at rest on the surface of the Earth will measure an Gravitational acceleration, acceleration due to Earth's gravity straight upwards of about Standard gravity, ''g'' ≈ 9.81 m/s2. By contrast, an accelerometer that is in free fall will measure zero acceleration. Accelerometers have many uses in industry, consumer products, and science. Highly sensitive accelerometers are used in inertial navigation systems for aircraft and missiles. In unmanned aerial vehicles, accelerometers help to stabili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismometer
A seismometer is an instrument that responds to ground displacement and shaking such as caused by quakes, 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 internal structure of Earth. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arica
Arica ( ; ) is a commune and a port city with a population of 222,619 in the Arica Province of northern Chile's Arica y Parinacota Region. It is Chile's northernmost city, being located only south of the border with Peru. The city is the capital of both the Arica Province and the Arica and Parinacota Region. Arica is located at the bend of South America's western coast known as the Arica Bend or Arica Elbow. At the location of the city are two valleys that dissect the Atacama Desert converge: Azapa and Lluta. These valleys provide citrus and olives for export. Arica is an important port for a large inland region of South America. The city serves a free port for Bolivia and manages a substantial part of that country's trade. In addition it is the end station of the Bolivian oil pipeline beginning in Oruro. The city's strategic position is enhanced by being next to the Pan-American Highway, being connected to both Tacna in Peru and La Paz in Bolivia by railroad and being ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antofagasta
Antofagasta () is a port city in northern Chile, about north of Santiago. It is the capital of Antofagasta Province and Antofagasta Region. According to the 2015 census, the city has a population of 402,669. Once claimed by Bolivia following the Spanish American wars of independence, Antofagasta was captured by Chile on 14 February 1879, triggering the War of the Pacific (1879–83). Chilean sovereignty was officially recognised by Bolivia under the terms of the 1904 Treaty of Peace and Friendship. The city of Antofagasta is closely linked to mining activity, being a port and the chief service hub for one of Chile's major mining areas. While silver and saltpeter mining have been historically important for Antofagasta, since the mid-19th century copper mining is by far the most important mining activity for Antofagasta, fueling a steady growth in the areas of construction, retail, hotel accommodations, population growth and skyline development until the end of the 2000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
