Magnitude 4.0 Earthquake Shakes San Jose: What Residents Need to Know

A magnitude 4.0 earthquake struck the San Jose area on Tuesday morning, June 11, 2024, at approximately 6:58 a.m. Local time, according to the United States Geological Survey (USGS). The quake’s epicenter was located about 22.4 kilometers (13.9 miles) northeast of San Jose, near the city of Milpitas, at a depth of approximately 8.5 kilometers (5.3 miles). While the tremor was widely felt across Silicon Valley, no injuries or significant structural damage have been reported as of this writing.

This event serves as a reminder of the region’s ongoing seismic activity and the importance of preparedness for residents living along the Pacific Ring of Fire.

Understanding the Quake: Location, Magnitude, and Impact

The USGS classified the earthquake as a light tremor on the moment magnitude scale, which measures the energy released during an earthquake. A magnitude 4.0 quake is typically felt indoors by many people and outdoors by few, often causing minor rattling of windows, doors, and unstable objects—but rarely resulting in damage.

Shaking intensity reached levels III to IV on the Modified Mercalli Intensity (MMI) Scale in parts of San Jose, Milpitas, Fremont, and Oakland. At MMI IV, shaking is noticeable indoors, with some people awakened, and loose objects may rattle or fall.

No tsunami warning was issued, as the quake occurred inland and lacked the offshore tectonic displacement necessary to generate a wave.

Why San Jose Is Prone to Earthquakes

The San Francisco Bay Area sits atop a complex network of fault lines, including the San Andreas, Hayward, and Calaveras faults. Tuesday’s quake occurred along the Calaveras Fault, a major branch of the San Andreas system capable of producing larger, more destructive events.

According to the USGS Earthquake Hazards Program, the Calaveras Fault has a roughly 20% probability of generating a magnitude 6.7 or greater earthquake in the next 30 years—a threshold considered capable of causing widespread damage in urban areas.

While magnitude 4.0 events like this one are relatively common in California—averaging several per year—they serve as critical stress indicators and opportunities for public education on earthquake readiness.

How to Prepare for Future Earthquakes

Experts from the California Earthquake Authority (CEA) and FEMA’s Ready Campaign recommend the following steps for residents:

• Secure your space: Anchor heavy furniture, water heaters, and appliances to walls. Use museum putty or hooks for fragile items on shelves.
• Create an emergency kit: Include water (one gallon per person per day for three days), non-perishable food, flashlights, batteries, a first-aid kit, and essential medications.
• Develop a family plan: Identify safe spots in each room (under sturdy tables, away from windows), establish communication protocols, and designate an out-of-area contact.
• Know how to react: During shaking, Drop, Cover, and Hold On. If indoors, stay inside until shaking stops. If outdoors, move to an open area away from buildings, trees, and power lines.
• Consider earthquake insurance: Standard homeowners’ policies typically do not cover earthquake damage. The CEA offers residential policies tailored to California’s risk profile.

residents can sign up for early warnings via the ShakeAlert® system, which provides seconds-to-minutes of alert before strong shaking arrives—potentially enough time to take protective action.

Recent Seismic Activity in the Region

Tuesday’s quake follows a series of smaller tremors in the Bay Area over the past month. On May 28, a magnitude 3.2 quake struck near Concord, and on June 2, a magnitude 3.5 event was recorded near Fremont. While none caused damage, the clustering highlights the tectonic stress building in the region.

Historically, the Bay Area has experienced devastating quakes, including the 1989 Loma Prieta earthquake (magnitude 6.9), which caused 63 deaths and over $6 billion in damages, and the 1906 San Francisco earthquake (estimated magnitude 7.9), which destroyed much of the city and led to widespread fires.

Although scientists cannot predict exactly when the next major quake will occur, they emphasize that it is not a matter of if, but when—making preparedness a lifelong necessity for Californians.

Key Takeaways

• A magnitude 4.0 earthquake shook San Jose and surrounding areas on June 11, 2024, at 6:58 a.m., with an epicenter near Milpitas.
• The quake was widely felt but caused no reported injuries or significant damage.
• It occurred along the Calaveras Fault, a known seismic hazard capable of producing larger, more destructive events.
• Residents are urged to prepare by securing their homes, building emergency kits, creating family plans, and considering earthquake insurance.
• Systems like ShakeAlert® can provide valuable early warnings—signing up is free and encouraged.

Frequently Asked Questions (FAQ)

Was this earthquake related to the San Andreas Fault?

No. While the San Andreas Fault runs nearby, this quake occurred on the Calaveras Fault, a separate but connected fault system. Both are part of the broader San Andreas tectonic boundary.

How common are magnitude 4.0 earthquakes in California?

Fairly common. California experiences dozens of magnitude 4.0–4.9 earthquakes each year, most of which cause little to no damage due to their depth and location.

Should I be worried about a bigger quake coming soon?

While any earthquake can theoretically be a foreshock, there is no way to know if a larger event will follow. However, the Bay Area has a high long-term risk of a magnitude 6.7+ quake within the next three decades, so ongoing preparedness is essential.

Can animals sense earthquakes before they happen?

Some anecdotal reports suggest animals may react to subtle precursors like ground tilting or gas releases, but scientific evidence remains inconclusive. The USGS states that reliable earthquake prediction is not currently possible.

Where can I get real-time earthquake alerts?

You can receive free alerts through the ShakeAlert® system via participating apps like MyShake, QuakeAlertUSA, or through wireless emergency alerts (WEA) on compatible smartphones.

Stay informed. Stay prepared. The ground may shake—but with readiness, we can stay safe.