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Shakealarm
ShakeAlarm is an on-site earthquake early warning system (EEWS) developed by Weir-Jones Engineering Consultants in Vancouver, British Columbia. The system functions by detecting and identifying fast moving P-waves that arrive before the slower and damaging S-waves generated from the hypocenter of an earthquake. Once ShakeAlarm has identified a candidate P-wave it will determine in less than 500 milliseconds if the following S-wave will be strong enough to be dangerous. Once the determination has been reached that an inbound S-wave might exceed acceptable levels the system can trigger the structured shutdown of critical processes - gas, electricity and water services - and can also be used for opening of fire bay doors, SMS warnings to the general population and a variety of other services to be activated before the S-wave's (shaking) impact. ShakeAlarm represents a streamlined site specific application of technology and ideas that Japan has been working with for some time on a nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vancouver, British Columbia
Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the city, up from 631,486 in 2016. The Greater Vancouver, Greater Vancouver area had a population of 2.6million in 2021, making it the List of census metropolitan areas and agglomerations in Canada#List, third-largest metropolitan area in Canada. Greater Vancouver, along with the Fraser Valley Regional District, Fraser Valley, comprises the Lower Mainland with a regional population of over 3 million. Vancouver has the highest population density in Canada, with over 5,700 people per square kilometre, and fourth highest in North America (after New York City, San Francisco, and Mexico City). Vancouver is one of the most Ethnic origins of people in Canada, ethnically and Languages of Canada, linguistically diverse cities in Canada: 49.3 percent of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-wave
A P wave (primary wave or pressure wave) is one of the two main types of elastic body waves, called seismic waves in seismology. P waves travel faster than other seismic waves and hence are the first signal from an earthquake to arrive at any affected location or at a seismograph. P waves may be transmitted through gases, liquids, or solids. Nomenclature The name ''P wave'' can stand for either pressure wave (as it is formed from alternating compressions and rarefactions) or primary wave (as it has high velocity and is therefore the first wave to be recorded by a seismograph). The name '' S wave'' represents another seismic wave propagation mode, standing for secondary or shear wave. Seismic waves in the Earth Primary and secondary waves are body waves that travel within the Earth. The motion and behavior of both P and S waves in the Earth are monitored to probe the interior structure of the Earth. Discontinuities in velocity as a function of depth are indicative of cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-wave
__NOTOC__ In seismology and other areas involving elastic waves, S waves, secondary waves, or shear waves (sometimes called elastic S waves) are a type of elastic wave and are one of the two main types of elastic body waves, so named because they move through the body of an object, unlike surface wave In physics, a surface wave is a mechanical wave that propagates along the Interface (chemistry), interface between differing media. A common example is gravity waves along the surface of liquids, such as ocean waves. Gravity waves can also occu ...s. S waves are transverse waves, meaning that the direction of particle motion of a S wave is perpendicular to the direction of wave propagation, and the main restoring force comes from shear stress. Therefore, S waves cannot propagate in liquids with zero (or very low) viscosity; however, they may propagate in liquids with high viscosity. The name ''secondary wave'' comes from the fact that they are the second type of wave to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facebook
Facebook is an online social media and social networking service owned by American company Meta Platforms. Founded in 2004 by Mark Zuckerberg with fellow Harvard College students and roommates Eduardo Saverin, Andrew McCollum, Dustin Moskovitz, and Chris Hughes, its name comes from the face book directories often given to American university students. Membership was initially limited to Harvard students, gradually expanding to other North American universities and, since 2006, anyone over 13 years old. As of July 2022, Facebook claimed 2.93 billion monthly active users, and ranked third worldwide among the most visited websites as of July 2022. It was the most downloaded mobile app of the 2010s. Facebook can be accessed from devices with Internet connectivity, such as personal computers, tablets and smartphones. After registering, users can create a profile revealing information about themselves. They can post text, photos and multimedia which are shared with any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
