Jared Brooks' New Madrid Earthquake Catalog

Jared Brooks was a resident of Louisville, Kentucky during the winter of 1811-12 who faithfully recorded the intensity of shaking experienced in that city throughout the main part of the earthquake sequence. To detect the smaller quakes, he constructed simple pendulums and set up springs to measure the smaller shaking often not felt by the residents in the region. Brooks was one of the first people to classify earthquakes by their shaking intensity and divided the New Madrid earthquakes into six strength categories: First Rate - Violent shaking Second Rate - Severe shaking Third Rate - Moderate, but alarming Fourth Rate - Perceptible, but not threatening Fifth Rate - (not defined) Sixth Rate - Observable with instruments The charts below illustrate the number of events and the pattern of the strong events that he observed.

The chart at the top shows the number of events in each week including all six categories (1,872 events), the chart below shows the 53 largest earthquakes from the three most intense categories (8 violent, 10 severe, and 35 moderate). The dots identify the weeks during which the three largest earthquakes in the sequence occurred: December 16, 1811; January 23, 1812; February 7, 1812.

SLU EQ Flyers | SLU EQ Center | Earth & Atmospheric Sciences Prepared by: Charles J. Ammon