Admin How does seismograph measure the magnitude of earthquake?
The Richter magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs. First the seismic moment is computed, and then it is converted to a magnitude designed to be roughly equal to the Richter Scale in the magnitude range where they overlap.
How do scientists measure earthquakes?
Earthquakes are recorded by a seismographic network. Each seismic station in the network measures the movement of the ground at that site. The Richter scale measures the largest wiggle (amplitude) on the recording, but other magnitude scales measure different parts of the earthquake.
How do scientists detect earthquakes?
Earthquakes are measured using instruments called seismometers, that detect the vibrations caused by seismic waves as they travel through the crust.
What is the magnitude of an earthquake?
Earthquake magnitude is a measure of the “size,” or amplitude, of the seismic waves generated by an earthquake source and recorded by seismographs. Richter first applied his magnitude scale to shallow-focus earthquakes recorded within 600 km of the epicentre in the southern California region.
How can scientists detect the magnitude and intensity of an earthquake?
A seismograph is the primary earthquake measuring instrument. The seismograph produces a digital graphic recording of the ground motion caused by the seismic waves. The digital recording is called a seismogram. A network of worldwide seismographs detects and measures the strength and duration of the earthquake’s waves.
How do scientists measure the size of an earthquake?
There are two ways in which scientists quantify the size of earthquakes: magnitude and intensity. You have probably heard of the Richter scale which is still used for small earthquakes, but most large earthquakes are now commonly reported using the moment magnitude scale (see below) .
What is an earthquake magnitude?
Magnitude is a measure of the amount of energy released during an earthquake, and you’ve probably heard news reports about earthquake magnitudes measured using the Richter scale. Something like, “A magnitude 7.3 earthquake struck Japan today. Details at ten.”
How do seismic stations measure the movement of the ground?
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. That vibration pushes the adjoining piece of ground and causes it to vibrate, and thus the energy travels out from the earthquake hypocenter in a wave.
Why is the Richter scale not used to measure earthquakes?
Seismologists today do not use the Richter scale as a universal tool for measuring earthquakes, because it does not accurately measure the energy emitted in jolts as big as the one that hit Japan. Instead, scientists use the moment magnitude scale, developed in the 1970s.