Question

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

Answer 1

9) Richter scale

10)Seismograph

11) measurement of the amplitude of the largest wave

I do believe to are correct

Answer 2

The correct answers are;  

9) Richter scale

10) Seismograph

11) measurement of the amplitude of the largest seismic wave

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.