Campus Alert Archive
Caltech

The Seismologists' Own Earthquake: M7.1 Ridgecrest Quake Rattles the Lab That Monitors It

CAearthquakeemergency notificationmedium confidence
Confirmed Threat

On July 5, 2019, a magnitude 7.1 earthquake struck near Ridgecrest, California, the largest Southern California earthquake in 20 years. The quake was felt strongly in Pasadena, where Caltech is home to the Seismological Laboratory that monitors earthquakes across the region. The university issued alerts advising building inspections and aftershock preparedness.

Alerts
2
Response
min
Killed
0
Injured
0
Institution
California Institute of Technology
Private R1 · CA
~2,200 studentsCaltech Alerts (Everbridge)
Confirmed Timeline

Alert Sequence

2 messages in sequence

Some alert texts below are approximate reconstructions from news coverage, not confirmed verbatim transcripts. Reconstructed texts are shown in italic with a dashed border. Verified verbatim texts have a solid border and are marked accordingly.

INITIAL ALERTSMS
Approximate reconstruction266 chars
Caltech Alert: A magnitude 7.1 earthquake has occurred near Ridgecrest, CA. Strong shaking was felt on campus. Check your surroundings for damage. If you smell gas, leave the building immediately. Expect aftershocks. Report damage to Campus Security at 626-395-5000.

This text has been reconstructed from news coverage and may not reflect the exact original wording.

Reconstructed from university communications and USGS reporting
The earthquake struck at 8:19 PM PDT with the epicenter approximately 120 miles northeast of Pasadena
Caltech's Seismological Laboratory recorded and analyzed the earthquake in real time
UPDATEEmail+13h 30m
Approximate reconstruction335 chars
Caltech Alert UPDATE: Building inspections are underway following last night's M7.1 earthquake. No structural damage has been identified so far. Minor cosmetic damage reported in several buildings. Continue to report any new damage. Aftershocks may continue for days or weeks. Review earthquake safety procedures at safety.caltech.edu.

This text has been reconstructed from news coverage and may not reflect the exact original wording.

Reconstructed from university post-earthquake communications
Caltech buildings are designed to seismic standards appropriate for Southern California
The irony of Caltech, home to the world's leading seismological research lab, being shaken by the largest local earthquake in two decades was widely noted in media coverage
Context

Background

On July 5, 2019, at 8:19 PM PDT, a magnitude 7.1 earthquake struck near Ridgecrest, California, approximately 120 miles northeast of Pasadena. It was the largest earthquake in Southern California since the 1999 M7.1 Hector Mine earthquake and followed a M6.4 foreshock the previous day. The shaking was felt strongly across the Los Angeles basin, including at the California Institute of Technology in Pasadena. Caltech occupies a unique position in earthquake science: the campus is home to the Seismological Laboratory, which operates the Southern California Seismic Network and has been at the forefront of earthquake research for nearly a century. Caltech seismologists were simultaneously experiencing the earthquake and analyzing its data in real time. The university issued alerts advising the campus community to check for damage and prepare for aftershocks. Building inspections found only minor cosmetic damage, reflecting the seismic engineering standards applied to campus structures. The Ridgecrest sequence produced thousands of aftershocks over the following weeks and reignited public conversation about earthquake preparedness in Southern California. For Caltech, the event was both a campus safety incident and a scientific opportunity, with researchers deploying instruments to the fault zone within hours.
Analysis

Key Findings

Caltech's dual role as both a campus needing to protect its community and the institution monitoring the earthquake created a unique situation
Building inspections found only cosmetic damage, reflecting robust seismic engineering standards
The largest Southern California earthquake in 20 years served as a real-world test of campus earthquake preparedness
Researchers deployed to the fault zone within hours, demonstrating the intersection of campus safety and scientific mission
Outcome
No injuries on campus. Minor cosmetic damage to some buildings. Building inspections completed with no structural concerns.
Provenance

Sources

  1. Official
    Caltech Seismological Laboratory - Ridgecrest Sequence
    seismolab.caltech.edu
  2. Source
    USGS - M7.1 Ridgecrest Earthquake
    earthquake.usgs.gov
  3. News
    Los Angeles Times - Ridgecrest earthquake coverage
    latimes.com
Tags
earthquakeridgecrestcaliforniaseismology-labbuilding-inspection
Added April 2026Updated May 2026Via ingestion