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AP Statistics chart assignment

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Chart 1 of 1 · Earthquakes

How much rarer is each step up in earthquake magnitude?

Chart: How much rarer is each step up in earthquake magnitude?

In 2025 the world recorded 6,428 earthquakes of magnitude 4.5 to 4.9, 1,983 of magnitude 5, 129 of magnitude 6, 15 of magnitude 7 and 1 of magnitude 8 or more. Each step up in magnitude is roughly ten times rarer, and releases about 32 times more energy. Countless smaller quakes go unrecorded worldwide, so the chart starts at 4.5.

Source: U.S. Geological Survey, ANSS Comprehensive Earthquake Catalog (ComCat) (Public domain (U.S. government work); source U.S. Geological Survey) · Data as of Dec 31, 2025

How to read this chart

Each bar counts the earthquakes recorded worldwide in one year within a range of magnitudes. The bars start at zero. Each whole step up in magnitude releases about 32 times more energy, so a magnitude 7 quake is far more than one step stronger than a 6.

Questions

  1. About how many times more earthquakes are there in each magnitude band than in the band above it?
  2. The counts fall by roughly the same factor each step. What kind of model fits that pattern, linear or exponential?
  3. If you took the logarithm of each count, what shape would you expect the graph to have, and why does that help?

Chart and numbers: chart.ly/charts/earthquakes-by-magnitude · More free charts at chart.ly