9. the scale most widely used by scientists for measuring earthquakes is the

seismic scale
richter scale
moment magnitude scale
epicenter magnitude scale

10. the instrument that records the seismic waves of an earthquake on paper is called a
seismograph
seismogram
richtergram
magnitude

the Richter magnitude of an earthquake is determined from the
duration of an earthquake
the intensity of an earthquake
arrival times of P waves and S waves
measurement of the amplitude of the largest seismic waves

The Richter scale is a scale of numbers that is commonly used by scientists to measure the size (magnitude) of earthquakes. To determine the size of an earthquake using this scale, the logarithm of the amplitude of the largest seismic wave is adjusted to a scale by a seismometer.

Seismograph is the instrument that records the seismic waves of an earthquake. A seismograph automatically detects and records the direction, intensity and duration of earthquakes. Seismograph is made up of a mass that is joined to a fixed base.