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...

California is known world-wide for its spectacular scenery. Recently, CGS conducted a photo contest where staff submitted their most awe-inspiring images of the state. Check out the pictures in the article and let us know which one is your favorite! www.conservation.ca.gov/cgs/document...

California is known world-wide for its spectacular scenery. Recently, CGS conducted a photo contest where staff submitted their most awe-inspiring images of the state. Check out the pictures in the article and let us know which one is your favorite! www.conservation.ca.gov/cgs/document...

Our staff are inspiring the next generation! Last week, Annie and Sara from the CGS Eureka office joined 250 students from Humboldt County at the at McKinleyville High School Career and Education Fair to talk about careers in geoscience. #GeoScienceMatters #Education

For over 50 years, the California Strong Motion Instrumentation Program has been collecting and disseminating valuable seismic data and products to increase public safety by enhancing rapid post-earthquake response capabilities and improving building codes for safer structures. 🧪

Last week, staff from CGS’s Burned Watershed Geohazard Program (BWG) attended and presented at the Floodplain Management Association’s first Post-Wildfire Watershed Management Symposium in Chico, CA.

Throughout the decades, the CGS library’s collections and holdings have steadily grown from just a few hundred works into an extensive assortment of both historical materials and current geoscience resources, numbering well over 100,000 items. www.conservation.ca.gov/cgs/document...

The 2024 wildfire season was active in California with 7,194 wildfire incidents resulting in just over one million acres burned by the end of October. www.conservation.ca.gov/cgs/document...

Thank you to everyone who came out to celebrate #EarthDay!

Come join us for #EarthDay and see important rocks and minerals of California, jump and make an earthquake, and learn about liquefaction! @calconservation.bsky.social

Please join us tomorrow, for an epic #EarthDay celebration! Tuesday, April 22, from 3-5 pm, 715 P St, DT Sacramento. Open to the public, free to attend, kids activities and more! Speak to reps from @cageosurvey.bsky.social and other CalConservation divisions. @canaturalresources.bsky.social

The California Geological Survey (CGS) collaborated with the California Department of Transportation (@CaltransHQ) to conduct statewide mapping of mineral hazards and paleontological resources. www.conservation.ca.gov/cgs/document...

The Sierra Nevada Earth Atlas showcases California’s longest and tallest mountain range and its iconic geologic features. It represents the most current, complete, and largest-scale, range-wide syntheses of geoscience data. Learn more - www.conservation.ca.gov/cgs/document...

Help power earthquake readiness! #Hiring an Assoc. Telecommunications Engineer to support CA's seismic network with @cageosurvey.bsky.social If you’re a hands-on problem solver who loves tech & fieldwork this is your chance to make a meaningful impact. youtu.be/iu0VdaE3DCY?...