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California Geological Survey @cageosurvey.bsky.social · 5d

To view the Earthquake Dashboard visit cadoc.maps.arcgis.com/apps/dashboa...

ArcGIS Dashboards

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California Geological Survey @cageosurvey.bsky.social · 5d

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.

Image contains 3 areas. On the left side is a map of California showing the locations of the earthquakes with different sized red dots. On the right is a bar graph showing the number of earthquakes in California over the past week.

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California Geological Survey @cageosurvey.bsky.social · 13d

To view the Earthquake Dashboard visit cadoc.maps.arcgis.com/apps/dashboa...

ArcGIS Dashboards

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California Geological Survey @cageosurvey.bsky.social · 13d

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.

Infographic with a map of California. Red dots of different sizes showing earthquake locations the location and relative magnitude of earthquakes in the past week. On the right is a bar graph showing the number of earthquakes of different sizes.

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California Geological Survey @cageosurvey.bsky.social · 19d

To view the Earthquake Dashboard visit cadoc.maps.arcgis.com/apps/dashboa...

ArcGIS Dashboards

cadoc.maps.arcgis.com

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California Geological Survey @cageosurvey.bsky.social · 19d

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.

Infographic with a bar graphic showing the number of earthquakes in California greater than a M2 that have occurred in the last week. Quake locations are marked by red dots on a map of California.

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California Geological Survey @cageosurvey.bsky.social · 20d

If you feel earthquake shaking or receive an earthquake alert you should drop down to the ground, take cover under a sturdy object, and hold on until all the shaking has stopped. www.shakeout.org/california/d...

Images showing the protective action you should take if you feel earthquake, shaking, or receive an earthquake alert.

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California Geological Survey @cageosurvey.bsky.social · 20d

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

Map of the San Francisco Bay area that shows the locations of strong motion stations which are marked by triangles. The colors on the map represent different levels of shaking with purples being weak shaking, blues being light shaking and green being moderate shaking.

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California Geological Survey @cageosurvey.bsky.social · 21d

We showed fossils & rocks and discussed topics like where to find trilobite fossils, how to stay safe during earthquakes, how Seismic Hazard Zone Maps work, and what a typical day in the life of a CGS geologist is like.

Thanks for joining us for this exciting event!

A man in a hat sits behind a table that has a tablecloth that says California Department of conservation California geological survey. On the table are an array of rocks and fossils.

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California Geological Survey @cageosurvey.bsky.social · 21d

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

A man sits behind a counter that is covered by rocks and fossil specimens. Two small children and an adult are talking with the man and looking at the rocks.

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California Geological Survey @cageosurvey.bsky.social · 22d

At the finish line were booths with information so participants could learn more about tsunami science and preparedness. Remember, if you are in a tsunami hazard zone and receive a warning or feel strong, prolonged shaking move inland and go towards high ground. www.tsunamizone.org

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California Geological Survey @cageosurvey.bsky.social · 22d

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.

A CGS employee stands with two event participants. He is showing them maps of tsunami hazard zones on an iPad.

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California Geological Survey @cageosurvey.bsky.social · 26d

To view the Earthquake Dashboard visit cadoc.maps.arcgis.com/apps/dashboa...

ArcGIS Dashboards

cadoc.maps.arcgis.com

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California Geological Survey @cageosurvey.bsky.social · 26d

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.

This image shows a map of California with the locations of the earthquakes plotted with red dots. Next to that is a bar graph showing the number of magnitude 2+ earthquakes and magnitude 3+ earthquakes as well as the large number “69“ to show the total number of earthquakes above a magnitude to.

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California Geological Survey @cageosurvey.bsky.social · Sep 8

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.

Map showing the location of earthquakes in California marked by red dots. There is a paragraph showing 42 earthquakes of magnitude two and four earthquakes of magnitude three.

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California Geological Survey @cageosurvey.bsky.social · Sep 4

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

A vivid cartoon image of different dinosaurs, including a T-Rex and a triceratops. The text says September 14, 2025 Dino fest.

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Reposted by California Geological Survey

California Department of Conservation @calconservation.bsky.social · Sep 3

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.

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California Geological Survey @cageosurvey.bsky.social · Sep 2

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...

Map of California showing the location of earthquakes that occurred in the last week. Earthquakes are marked by red dot. The total number of earthquakes greater than a magnitude 2 in California last week was 35.

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California Geological Survey @cageosurvey.bsky.social · Jul 30

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...

Petropavlovsk-Kamchatsky 2025 - Tsunami Emergency Reconnaissance - Maritime

Petropavlovsk-Kamchatsky July 2025 Tsunami Emergency Reconnaissance Maritime Questionnaire

survey123.arcgis.com

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California Geological Survey @cageosurvey.bsky.social · Jul 17

If you feel earthquake shaking or receive an earthquake alert, drop down to the ground, take cover underneath a sturdy object, and hold on until all the shaking has stopped. www.caloes.ca.gov/office-of-th...

Earthquake Preparedness | California Governor's Office of Emergency Services

www.caloes.ca.gov

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California Geological Survey @cageosurvey.bsky.social · Jul 17

While the highest hazard areas are near major active faults, damaging earthquake shaking is possible anywhere in the state.

Factors like proximity to faults and local geologic conditions influence shaking intensity.

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California Geological Survey @cageosurvey.bsky.social · Jul 17

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...

Map of California that shows shaking intensity represented by colors scaling from light yellow to dark red. The darkest red colors follow the major faults, and the valleys are red to dark orange. The Sierra Nevada Mountains and the eastern most part of California are light yellow.

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California Geological Survey @cageosurvey.bsky.social · Jul 7

The insights gained from shake table research contribute to a broader understanding of earthquake engineering and earthquake monitoring, ultimately leading to safer, more resilient buildings and communities.

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California Geological Survey @cageosurvey.bsky.social · Jul 7

Inside this building, they have collocated 33 high-resolution seismometers with 33 lower-resolution seismometers. The goal is to collect data from these instruments and compare the results to learn about the capabilities and limitations of lower resolution, lower cost instrumentation.

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California Geological Survey @cageosurvey.bsky.social · Jul 7

Shake tables are also used to evaluate seismic equipment. In the test shown above, the California Geological Survey’s Strong Motion Instrumentation is testing different kinds of seismometers.

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