For Second Time in September, Carnegie’s Seismometer Records Devastating Mexican Earthquake

Tuesday, September 19, 2017 

A magnitude 7.1 earthquake struck Raboso, a small town located 65 miles southeast of Mexico City on Tuesday, September 19. The earthquake is substantially closer to the Mexican capital than the magnitude 8.1 earthquake that struck 10 days ago off the coast of Chiapas, Mexico.

The seismic record shown here was recorded on the seismometer located on Carnegie's Broad Branch Road campus. These seismometers are installed to record ground motion near sensitive equipment while nearby construction projects are ongoing, but they also serve to record ground motions from large events that occur anywhere on the planet.

The screenshot shown was taken during the very first look at the data. The three seismograms in the graph show three components (vertical, North-South, and East-West) of ground velocity (uncalibrated), all measured simultaneously by the same instrument.


Preliminary reports indicate significantly more widespread damage to structures in Mexico City from the event today, due to its proximity.


The event today occurred on the 32nd anniversary of the devastating 1985 Mexico City earthquake that resulted in thousands of fatalities and widespread destruction. Mexico City is particularly vulnerable to earthquake damage because large portions of the city are built on lakebed sediments that are more prone to strong shaking than solid rock.