Between February 2 (12:00 AM PST) and February 8 (11:59 PM) there were 36 earthquakes in California of magnitude 2.0 or larger. 🔸97 earthquakes between M2.0 - 2.9 🔸8 earthquakes between M3.0 - 3.9 🔸2 earthquakes between M4.0 - 4.9 The largest earthquake was a magnitude 3.7 west of Petrolia, CA.

Between January 26 (12:00 AM PST) and February 1 (11:59 PM) there were 36 earthquakes in California of magnitude 2.0 or larger. 🔸31 earthquakes between magnitude 2.0 - 2.9 🔸5 earthquake between magnitude 3.0 - 3.9 The largest earthquake was a magnitude 3.4 near San Ramon, CA.

Between January 19 (12:00 AM PST) and January 25 (11:59 PM) there were 83 earthquakes in California of magnitude 2.0 or larger. 🔸70 earthquakes between M2.0 - 2.9 🔸10 earthquake between M3.0 - 3.9 🔸3 earthquake between M4.0 - 4.9 The largest earthquake was a magnitude 4.9 near Indio, CA.

Between January 12 (12:00 AM PST) and January 20 (8:30 AM) there were 85 earthquakes in California of magnitude 2.0 or larger. 🔸65 earthquakes between M2.0 - 2.9 🔸16 earthquake between M3.0 - 3.9 🔸4 earthquake between magnitude 4.0 - 4.9 The largest earthquake was a magnitude 4.9 near Indio, CA.

32 years ago, at 4:31 AM, a magnitude 6​.7 earthquake struck southern California. This quake, centered in Northridge, caused 57 fatalities and injured thousands.

Between January 5 (12:00 AM PST) and January 11 (11:59 PM) there were earthquakes in California of magnitude 2.0 or larger. 🔸38 earthquakes between M2.0 - 2.9 🔸4 earthquake between M3.0 - 3.9 🔸1 earthquake between M4.0 - 4.9 The largest earthquake was a magnitude 4.2 near Cloverdale, CA.

The California Geological Survey offers a variety of interactive web maps, including geologic and geohazard maps, mineral resource maps, and earthquake regulatory zone maps. These maps can be found here: maps.conservation.ca.gov/cgs/#datalist

Geologic mapping of California continues with the Regional Geologic & Landslide Mapping Program. Maps include statewide geologic and fault activity maps, geologic atlas and regional geologic map series, and offshore continental margin maps. www.conservation.ca.gov/cgs/rgm/prog...

Between December 29 (12:00 AM PST) and January 4 (11:59 PM) there were 52 earthquakes in California of magnitude 2.0 or larger. 🔸50 earthquakes between M2.0 - 2.9 🔸1 earthquake between M3.0 - 3.9 🔸1 earthquake between M4.0 - 4.9 The largest earthquake was a magnitude 4.9 near Susanville, CA.

135 years have passed since the preparation of the 1891 Preliminary Mineralogical and Geological Map of the State of California. This webpage walks you through the history and evolution of geologic maps of California. www.conservation.ca.gov/cgs/rgm/hist...

Geologic mapping in California began about 180 years ago. The first geologic mapping in the State was done by Lieutenant Edward Belcher, a British naval officer. Although Belcher did the surveying for the map in 1826, it was not published until 1839. www.conservation.ca.gov/cgs/rgm/hist...

In 1851 Dr. John B. Trask was named as “State Geologist”. Today, the CA State Geologist is Jeremy Lancaster. He leads the @cageosurvey.bsky.social in providing scientific products and services about the state's geology, seismology, geohazards, and minerals. www.conservation.ca.gov/cgs/about/hi...

Between December 22 (12:00 AM PST) and December 28 (11:59 PM) there were 61 earthquakes in California of magnitude 2.0 or larger. 🔸57 quakes between M2.0 - 2.9 🔸3 quakes between M3.0 - 3.9 🔸1 quake between M4.0 - 4.9 The largest earthquake was a magnitude 4.7 near Susanville, CA.

California Geotour is an index of field trip information for people interested in visiting California's world-famous geologic features. This site contains geologic information, photographs, maps & directions for interesting geologic locations across the state. www.conservation.ca.gov/cgs/californ...

Between December 15 (12:00 AM PST) and December 21 (11:59 PM) there were 94 earthquakes in California of magnitude 2.0 or larger. 🔸83 quakes between M2.0 - 2.9 🔸11 quakes between M3.0 - 3.9 The largest earthquake was a magnitude 3.9 near San Ramon, CA.

Between December 8 (12:00 AM PST) and December 14 (11:59 PM) there were 102 earthquakes in California of magnitude 2.0 or larger. 🔸90 quake between M2.0 - 2.9 🔸11 quake between M3.0 - 3.9 🔸1 quake between M4.0 - 4.9 The largest earthquake was a M4.0 near Glen Ellen, CA.

Between December 1 (12:00 AM PST) and December 7 (11:59 PM) there were 44 earthquakes in California of magnitude 2.0 or larger. 🔸40 earthquakes between magnitude 2.0 - 2.9 🔸4 earthquakes between magnitude 3.0 - 3.9 The largest earthquake was a magnitude 3.4 near Fortuna, CA.

Did you know that Serpentinite is California’s state rock? Serpentinite is green to black & is often mottled with light & dark colored areas. It’s mainly found in central & northern California in the Coast Ranges, Klamath Mountains & Sierra Nevada foothills. www.conservation.ca.gov/cgs/Document...

Between November 24 (12:00 AM PST) and November 30 (11:59 PM) there were 66 earthquakes in California of magnitude 2.0+. -50 quakes between M2.0 - 2.9 -15 quakes between M3.0 - 3.9 -1 quakes between M4.0 - 4.9 The largest quake was a magnitude 4.0 near San Juan Bautista.

Did you know that Benitoite is the California state gem? Benitoite can occur in rich blue crystals that are as striking and flawless as the finest sapphires. Gem quality benitoite is found only in a small area of San Benito County, California. 🧪 ⚒️ www.conservation.ca.gov/cgs/Document...

Are you traveling over the holiday weekend? Be sure to check out some of California’s “Geo Gems” - notable geologic features in California state parks. These geologic wonders illustrate the legacy and continuing geologic evolution of California.   www.parks.ca.gov?page_id=29631

Between November 17 (12:00 AM PST) and November 23 (11:59 PM) there were 41 earthquakes in California of magnitude 2.0 or larger. -36 quakes between M2.0 - 2.9 -4 quakes between M3.0 - 3.9 -1 quake between M4.0 - 4.9 The largest earthquake was a M4.1 near Templeton, CA.

Between November 10 (12:00 AM PST) and November 16 (11:59 PM) there were 37 earthquakes in California of magnitude 2.0 or larger. 🔸33 earthquakes between magnitude 2.0 - 2.9 🔸4 earthquakes between magnitude 3.0 - 3.9 The largest earthquake was a magnitude 3.5 near Vallejo, CA.

Between November 3 (12:00 AM PST) and November 9 (11:59 PM) there were 50 earthquakes in California of magnitude 2.0 or larger. 🔸45 quakes between magnitude 2.0 - 2.9 🔸5 quakes between magnitude 3.0 - 3.9 The largest earthquake was a magnitude 3.8 near San Ramon, CA.

Between October 27 (12:00 AM PST) and November 2 (11:59 PM) there were 43 earthquakes in California of magnitude 2.0 or larger. 🔸39 earthquakes between magnitude 2.0 - 2.9 🔸4 earthquakes between magnitude 3.0 - 3.9 The largest earthquake was a magnitude 3.5 west of Petrolia, CA.

This past week we had 58 earthquakes in California of magnitude 2+. Is that more earthquakes than usual? Not really. For instance, during September and October 2025, California averaged 49 earthquakes a week. However, the actual number varies from week to week. 1/

Between October 20 (12:00 AM PST) and October 27 (9:00 AM) there were 58 earthquakes in California of magnitude 2.0 or larger. -50 quakes between M2.0 - 2.9 -8 quakes between M3.0 - 3.9 The largest earthquakes were both magnitude 3.5. One occurred near Petrolia and the other was near Redway.

The Great ShakeOut Earthquake drill was a success! Thanks to everyone who joined us across California and around the world. Remember, if you feel earthquake shaking or receive an earthquake alert, drop down, take cover, and hold on. @calconservation.bsky.social

Between October 13 (12:00 AM PST) and October 19 (11:59 PM) there were 49 earthquakes in California of magnitude 2.0 or larger. -48 quakes between magnitude 2.0 - 2.9 -1 quake between magnitude 3.0 - 3.9 The largest earthquake was a magnitude 3.1 near Hayfork, CA.

Happy Geologic Map Day! The @cageosurvey.bsky.social produces geologic maps at various scales & derivative maps showing important aspects of geologic hazards or resources. #EarthScienceWeek

It’s National Fossil Day! Learn more about the work that the CGS has done with Caltrans mapping mineral hazards & paleontological resources along the highway system. #EarthScienceWeek www.conservation.ca.gov/cgs/documents/publications/california-geology-magazine/CG_2024-MineralHazardsFossils.pdf

Happy #EarthScienceWeek! The theme for today is Minerals. At the @cageosurvey.bsky.social our Mineral Resources Program provides data about California's mineral resources, mineral hazards, and active and historic mining activities. Learn more ➡️ www.conservation.ca.gov/cgs/minerals...

Between October 6 (12:00 AM PST) and October 12 (11:59 PM) there were 58 earthquakes in California of magnitude 2.0 or larger. 🔸57 earthquakes between magnitude 2.0 - 2.9 🔸1 earthquake between magnitude 3.0 - 3.9 The largest earthquake was a magnitude 3.2 near Pinnacles, CA.

California Weekly Earthquake Report Between September 29 (12:00 AM PST) and October 5 (11:59 PM) there were 40 earthquakes in California of magnitude 2.0 or larger. 🔸34 quakes between magnitude 2.0 - 2.9 🔸6 quakes between magnitude 3.0 -3.9 The largest was a magnitude 3.5 near Big Bear, CA.

California Weekly Earthquake Report Between September 22 (12:00 AM PST) & September 28 (11:59 PM) there were 31 earthquakes in CA of magnitude 2.0 or larger. -30 quakes between M2.0 - 2.9 -1 quake between M4.0 - 4.9 The largest was a magnitude 4.3 earthquake near Berkeley.

California Weekly Earthquake Report Between September 15 (12:00 AM PST) & September 21 (11:59 PM) there were 43 earthquakes in CA of magnitude 2.0 or larger. -41 quakes between M2.0 - 2.9 -2 quakes between M3.0 - 3.9 The largest was a magnitude 3.3 earthquake near Clayton.

At 2:56 AM a magnitude 4.3 earthquake occurred near Berkeley, CA. The earthquake location is close to the Hayward fault. This earthquake generated light shaking across the Bay Area. The CGS continues to monitor the situation. www.conservation.ca.gov/cgs

On Sept. 15th, CGS participated in the 10th Annual Dino Fest at the @nhm.org!

This past weekend CGS geologists participated in the Santa Cruz’s “Race the Wave” event to raise awareness about tsunamis. The race path took participants along the tsunami evacuation route from the beach to high ground.

California Weekly Earthquake Report Between September 8 (12:00 AM PST) and September 14 (11:59 PM) there were 69 earthquakes in California of magnitude 2.0 or larger. -56 quakes between M2.0 - 2.9 -13 quakes between M3.0 - 3.9 The largest was a magnitude 3.7 near Maricopa, CA.

California Weekly Earthquake Report Between September 1 (12:00 AM PST) and September 7 (11:59 PM PST) there were 46 earthquakes in California of magnitude 2.0 or larger. - 42 quakes between M 2.0 - 2.9 - 4 quakes between M 3.0 - 3.9 The largest was a magnitude 3.7 near Los Pinos, CA.

Join us on Sept. 14th for @nhm.org 10th Annual #DinoFest! Geologists from CGS will be on site with a table full of rocks, fossils, maps, and hands-on activities. Save your spot today: nhm.org/dinofest

After the July 29 M8.8 #KamchatkaQuake, @cageosurvey.bsky.social scientists documented #tsunami impacts at Dana Point. Orange County Sheriff Harbor Patrol reported surges up to 10–12 mph rushing in/out, damaging a bait barge & challenging vessels in the harbor. Data helps refine CA hazard #maps.

California Weekly Earthquake Report Between August 25 (12:00 AM PST) and August 31 (11:59 PM PST) there were 35 earthquakes in California of magnitude 2.0 or larger. The largest was a magnitude 2.9 near Dunsmuir, CA. cadoc.maps.arcgis.com/apps/dashboa...

The @cageosurvey.bsky.social is gathering observations about the tsunami generated by the M8.8 Kamchatka earthquake. If you are in CA and made any first-hand observations of the tsunami or the evidence left behind by the tsunami please fill out this survey. survey123.arcgis.com/share/76979d...

California Earthquake Shaking Potential Map This updated map shows how hard the ground could potentially shake from earthquakes in California. www.conservation.ca.gov/cgs/sh/earth...

This 10-story building is constructed on a high-performance shake table at the UCSD Englekirk Structural Engineering Center, and it is about to experience the same ground shaking that occurred in Gilroy, CA, during the 1989 magnitude 6.9 Loma Prieta earthquake.

Today marks 6 years since the magnitude 7.1 Ridgecrest earthquake, the largest earthquake to strike California in 20 years. This earthquake provided valuable data for understanding complex fault systems and highlighted the need for improved earthquake preparedness. @calconservation.bsky.social 🧪

DWR’s Statewide Airbourne Electromagnetic Survey Project has delivered approximately 16,000 miles of high-quality airborne geophysical data across California’s priority groundwater basins.

The 2019 Ridgecrest earthquakes provided an opportunity to collect a rich and unique set of observations that can be used to improve our understanding of earthquakes, test new technologies & allow us to better prepare for future earthquakes. 🧪 www.conservation.ca.gov/cgs/document...