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- Each seismograph gives the distance from that station to the earthquake epicenter. Three or more seismograph stations are needed to locate the epicenter of an earthquake through triangulation. Using the arrival-time difference from the first P wave to the first S wave, one can determine the distance from the epicenter, but not the direction.
The simplest method of locating an earthquake on a globe is to find the time interval between the P- and S-wave arrivals at several seismograph stations. The distance to the earthquake from each station is then determined from standard travel-time tables and travel-time curves.
People also ask
How do seismograms measure earthquake intensity?
How do seismic networks measure earthquakes?
How do you know if a seismogram is a earthquake?
How are earthquakes recorded?
Earthquakes are recorded by a seismographic network. Each seismic station in the network measures the movement of the ground at that site. The slip of one block of rock over another in an earthquake releases energy that makes the ground vibrate.
A seismograph produces a graph-like representation of the seismic waves it receives and records them onto a seismogram (Figure below). Seismograms contain information that can be used to determine how strong an earthquake was, how long it lasted, and how far away it was.
Seismographic networks measure earthquakes by their magnitude, energy release and intensity. Years ago, all magnitude scales were based on the recorded waveform lengths or the length of a seismic wave from one peak to the next.
The seismograph has a base that sets firmly in the ground, and a heavy weight that hangs free. When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the hanging weight does not.
We use exaggerated motion of a building (seismic station) to show how the ground moves during an earthquake, and why it is important to measure seismic waves using 3 components: vertical, N-S, and E-W.
May 10, 2011 · Seismographs are set to measure seismic waves at specific frequencies — say, at a frequency of one hertz, or a period of one second, for a type of body wave called a P-wave; or 50 millihertz, a period of 20 seconds, for surface waves.
