Difficult# Earthquake Depth and Magnitude

GMAT-VWG547

For one calendar year, data on the magnitude (on the Richter Scale) and depth (in kilometers) of every earthquake recorded around the world was compiled. There were over $17,000$ earthquakes recorded. Below is a scatterplot of the depth and magnitude of the earthquakes:

The graphs below are percentile plots. The percentiles of the magnitude measurements are graphed at left, while the percentiles of the depth measurements are graphed at right.

**Part 1:**

At which of the following depths was there the greatest variability in magnitude recorded?

**Part 2:**

Approximately what percent of all earthquakes appear to have a magnitude greater than $5.0$ on the Richter scale?

**Part 3:**

Estimate the median depth of an earthquake.

**Part 4:**

On the Richter Scale, a magnitude $6.0$ earthquake is ten times as intense as a magnitude $5.0$ earthquake. Each increase of $1.0$ units on the Richter scale is a ten-fold increase in intensity.

Find the approximate difference in percentile ranks between a magnitude $3.0$ earthquake and an earthquake that is $1,000$ times more intense.