Earthquake Near Cloverdale: What You Need to Know (July 28, 2020)

What Happened?

On Tuesday evening, July 28, a magnitude 4.3 earthquake shook the area east‑southeast of Cloverdale, California. Less than a minute later, a magnitude 2.5 aftershock followed in nearly the same spot. The U.S. Geological Survey (USGS) recorded both events and says the quakes were centered near The Geysers geothermal area, a place where small earthquakes are common.

The Main Quake

• Time: 7:40 p.m. (local time)
• Location: About 5 miles southeast of Cloverdale
• Depth: Roughly 3.4 miles underground
• Magnitude: 4.3 (a “light” to “moderate” shake)

The Aftershock

• Time: 38 seconds after the main quake
• Location: Almost the same spot as the main quake
• Depth: About 2.6 miles underground
• Magnitude: 2.5 (usually felt only by people very close to the epicenter)

Why This Area? (The Geysers)

The Geysers is a large geothermal field where hot water and steam are pumped from deep underground to generate electricity.

• Frequent small quakes happen there because injecting and removing fluids changes pressure in the rocks.
• Scientists consider this normal for the region, not a sign of a bigger, dangerous earthquake.

Community Response

“Good‑sized shaker,” said State Senator Mike McGuire (whose district includes northern Sonoma County) on Facebook. “No early reports of damage or injuries.”

As of Wednesday morning, no injuries or significant damage have been reported.

How to Report Your Experience

The USGS runs a program called “Did You Feel It?” to collect real‑world shaking reports. Your input helps scientists understand how far the quake was felt and how strong it seemed in different places.

Steps to submit a report:

1. Go to the USGS “Did You Feel It?” website (or use the USGS app).
2. Enter your location (address, city, or GPS coordinates).
3. Choose the shaking intensity you felt (e.g., “light,” “moderate,” “strong”).
4. Add any details (e.g., “pictures fell,” “felt a sway”).
5. Click Submit.

Important: Even if you only felt a tiny wobble, your report matters! It builds a better picture for everyone.

Shaking Reports So Far

• Cloverdale (near the epicenter): Light shaking
• Ukiah (about 30 miles north): Very light shaking

Summary

• A magnitude 4.3 earthquake hit near Cloverdale at 7:40 p.m. on July 28, followed 38 seconds later by a magnitude 2.5 aftershock.
• Both quakes were shallow (2.6–3.4 miles deep) and centered near The Geysers, a geothermal area known for frequent small quakes.
• No injuries or major damage have been reported.
• The USGS encourages anyone who felt the shaking to file a “Did You Feel It?” report to help improve earthquake science.

FAQ

1. What does “magnitude 4.3” mean in simple terms?
Magnitude measures the energy released at the earthquake’s source. A 4.3 quake is considered light to moderate—strong enough to be felt widely but rarely causes serious damage.

2. What is an aftershock?
An aftershock is a smaller earthquake that follows the main shock in the same general area. They happen as the ground adjusts to the stress changes caused by the bigger quake.

3. Why do earthquakes happen at The Geysers?
The Geysers is a geothermal power plant where water is injected deep underground and steam is extracted. Changing fluid pressure underground can cause the rock to slip, creating small earthquakes.

4. Should I be worried about a bigger quake coming soon?
Small quakes and aftershocks are normal in this area. While no one can predict earthquakes, there’s no indication this sequence signals a larger, damaging event.

5. How can I stay safe during an earthquake?

• Drop, Cover, and Hold On: Get under a sturdy table or desk, protect your head, and hold on until shaking stops.
• After the shaking, check for hazards (gas leaks, broken glass) and follow local emergency guidance.

You can reach Staff Writer Isabel Beer at isabel.beer@pressdemocrat.com for more information.