8. which statement best describes the richter scale?
a. it's named after a scientist who studied tornadoes.
b. it's a numerical rating system that measures the largest seismic waves during an earthquake.
c. it's a test given to all geologists.
d. it's a numerical system that measures the smallest seismic waves during an earthquake.

Answer;

D. It's a numerical system that measures the smallest seismic waves during an earthquake.

Explanation;

-The Richter magnitude scale is a scale of numbers used to tell the size of earthquakes. It is a standard scale used to compare earthquakes. The scale was invented by Charles Francis Richter and was based on the seismogram measured by a particular type of seismometer at a distance of 100 kilometres (62 mi) from the earthquake.

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.