Chart assignment

Charts to read and discuss

Read each chart, then answer its questions. Every chart shows its source and date; open it for a table of the numbers and the data to download.

  1. How many major earthquakes happen each year?
  2. Which big U.S. cities have the most violent crime?

Chart 1 of 2 · Earthquakes

How many major earthquakes happen each year?

The interactive chart needs JavaScript. The numbers are on the chart's page.

The world had 16 earthquakes of magnitude 7 or more in 2025. Since 1900 the yearly count has ranged from 4 in 1930 to 24 in 2010, with no lasting rise. Quakes this strong are recorded wherever they strike, so even early counts are fairly complete; magnitudes before the 1960s are scientists' later estimates from old seismograms.

Questions to discuss

  1. In one sentence of your own, what does this chart show?
  2. Find the biggest change or difference in the chart. What might explain it?
  3. Who collected these numbers, and how recent are they? What else would you want to know before drawing a conclusion?

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

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Chart 2 of 2 · Crime

Which big U.S. cities have the most violent crime?

The interactive chart needs JavaScript. The numbers are on the chart's page.

In 2025, Memphis, TN had the highest violent crime rate of the 89 biggest U.S. cities whose police reported a full year to the FBI, about 1,853 per 100,000 people, followed by Detroit, MI (1,654) and Oakland, CA (1,475). Irvine, CA (79) and Virginia Beach, VA (101) had the lowest; the U.S. rate was about 330. Violent crime is murder, rape, robbery and aggravated assault. In 2025 the police in New Orleans, Orlando and St. Petersburg, Florida, didn't report a full year of crimes, so they are left out. Each rate is per person the department serves, and a few, such as Las Vegas, Honolulu, Jacksonville and Louisville, serve their whole county. A city's rate also depends on where its borders fall, so compare cities with care.

How to read this chart

Each bar is one big city's violent crimes reported to the FBI in a year (murder, rape, robbery and aggravated assault) for every 100,000 people its police department serves. The dashed line is the rate for the whole U.S. Dividing by population makes big and small cities fair to compare, but a city's rate also depends on where its borders fall.

Questions to discuss

  1. Find the city with the highest rate and the one with the lowest. About how many times higher is the top rate?
  2. Some departments police a whole county, suburbs included. How could that change a city's rate compared with one that covers only its downtown?
  3. These are crimes reported to police. What kinds of crime might never show up in these numbers, and why?

Source: FBI Crime Data Explorer, Uniform Crime Reporting Program (Public domain (U.S. government work); source FBI Uniform Crime Reporting Program) · Data as of Dec 31, 2025

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