The 2019 Ridgecrest Earthquake Sequence
In July 2019, two significant earthquakes struck a sparsely populated area of Southern California near the city of Ridgecrest. A magnitude 6.4 foreshock hit on July 4, followed by a magnitude 7.1 mainshock on July 5. The effects of both were felt throughout Southern California and as far away as Las Vegas. The magnitude 7.1 mainshock was the most powerful earthquake in the state of California in 20 years.
How Earthquakes Cause Structural Damage
Earthquakes cause damage primarily by shaking the ground, which can lead to:
- Structural damage to foundations, framing, walls, and load-bearing elements
- Severing of mechanical lines including gas, water, and electrical systems
- Power outages from damaged electrical infrastructure
- Secondary hazards such as fires from ruptured gas lines and landslides from destabilized slopes
The severity of damage depends on several factors including the earthquake's magnitude, depth, distance from the epicenter, local soil conditions, and the age and construction type of the building.
Lessons for Property Owners
The Ridgecrest sequence demonstrated that major earthquakes can strike with little warning and that foreshocks can precede even larger events. Property owners throughout California and the western United States should consider having their buildings assessed for seismic vulnerability, particularly if the structure was built before modern seismic building codes were adopted.
After any significant earthquake, a professional structural evaluation is essential to identify damage that may not be visible to the untrained eye and to document conditions for insurance claims.
Earthquake Damage Resource provides expert earthquake damage assessment and forensic engineering guidance throughout California and nationwide. If your property has sustained earthquake damage, contact our team for a professional evaluation.