#EQ History: 1960 M9.5 Chilean EQ occurred on this day. Signals from this event, recorded on a Benioff strainmeter at SCSN station CI.ISA, were the first conclusive observations of the Earth's free oscillations, including the gravest spheroid mode (aka "football mode") at 54 min.

#FieldPhotoFriday from Hungry Valley, CA! After some serious digging at this site, our team swapped out worn batteries and updated the equipment to keep this station running smoothly. As part of the #ShakeAlert EEW System, it helps keep 50+ million people on the West Coast safe!

Last month during #SSA2026, the Seismo Lab hosted an Alumni Reunion here at the Lab! With so many former students, researchers, staff, and collaborators already in Pasadena for the meeting, it was wonderful to see the halls filled with familiar faces once again. buff.ly/wSLXae5

Weekly Earthquake Stats: 10 May 2026 - 16 May 2026. There were 822 events this week ranging from M -0.11 to 4.66. Check out our weekly playback map and visit www.scsn.org for detailed information. #earthquakes #seismology #SCSN #weeklystats @CaltechSeismo

#FieldPhotoFriday This station near Lake Casitas has been recording data since 2019 when it was installed, but just recently started having power problems at night. A new set of batteries to replace the original ones, and a little bit of weeding, and hopefully it will be good for another 7 years!

Meet Rajani Shrestha, a Seismo Lab Grad Student who specializes in Geometrical distribution of seismicity; earthquake cycle simulations; time-dependent earthquake forecasting! #SeismoLabSpotlight

Weekly Earthquake Stats: 03 May 2026 - 09 May 2026. There were 335 events this week ranging from M -0.31 to 3.83. Note: This info and map ends at 5pm PDT May 9, just shortly after the first M3.5+ events began occurring in the Brawley Swarm.

Did you know that when someone is talking about felt earthquake, if they mention the Richter Scale, they are probably actually talking about the Tom Hanks (no not that Tom Hanks!) and Hiroo Kanamori Moment Magnitude!

This sequence is ongoing with an additional M4.3 that just happened at 8:39 PDT, you can see the events in the sequence as their waves cross the Southern California Seismic Network on our Live Seismograms Feed buff.ly/rL6Y9t7 And if you felt it, tell the scientists at buff.ly/9EGxt8p

A swarm sequence has been confirmed near #Brawley, CA, #SouthernCalifornia #Earthquake. This is a typical sequence for the area, with with 81 events catalogued so far, including a M4.4 at 7:22 PDT. You can read more about it here: www.scsn.org/index.php/20...

#FieldPhotoFriday New tech, preventative maintenance, and repairs are common reasons for the Field Crew to visit a station throughout the years since it was installed. This station near Johnson Valley, est. 2001, is a good example. This work keeps us strong and ready for the next bit of shaking!

#FieldPhotoFriday It may not be exciting like Kilauea, but we do have volcanic regions in SoCal, which is why we monitor specific "Swarm Regions" more here: buff.ly/kr8wRSb Anyway... here is a station that had some maintenance recently... that is literally right next to an old volcano in the Mojave!

This week, Marcos Alvarez, SCSN Manager with the USGS, is retiring after more than a decade overseeing the expansion and maintenance of the SCSN’s seismic network. Please join us in wishing Marcos all the best in this next chapter and an exciting new journey ahead!

Weekly Earthquake Stats: 19 Apr 2026 - 25 Apr 2026. There were 233 events this week ranging from M -0.06 to 3.27. Check out our weekly playback map and visit www.scsn.org for detailed information. #earthquakes #seismology #SCSN #weeklystats @CaltechSeismo

M3.6 10km NNE of #Cabazon, CA, #SouthernCalifornia #Earthquake confirmed valid. Updated analysis coming soon @ www.scsn.org/index.php/earthquakes/latest-earthquake-information/

Since 1981, this station in Leona Valley has been quietly recording Earth’s motions. From its solar panel to steel vault, every instrument plays a role in capturing high-quality seismic data. Shout out to our field crew for consistently taking on the desert heat to keep our stations running strong!

A view from the Operations Center, AKA the Timer’s Room. This is where seismic analysts (Timers) monitor earthquakes, with a wall of windows looking into the Caltech Media Center, where major post-earthquake press conferences and interviews are often held.

Weekly Earthquake Stats: 12 Apr 2026 - 18 Apr 2026. There were 281 events this week ranging from M -0.33 to 3.54. Check out our weekly playback map and visit www.scsn.org for detailed information. #earthquakes #seismology #SCSN #weeklystats @CaltechSeismo

#FieldPhotoFriday Big Rocks, sprawling views, and what... seismic data? Looks like the crew are one highway turn off away from Perfection, Nevada! Glad the crew got all of their recent equipment upgrades done before the Graboids got there! (IYKYK)

#SSA26 Aparna Bhaskaran is presenting: What's new at the SCEDC & SCSN: Data Products, Services and Tools for Seismic Data in Southern California #SCSN #SCEDC #Seismology

#SSA26 Igor Stubailo is presenting: System Monitoring, Telemetry Quality Control and DAS Testing at SCSN #SCSN #Seismology #Telemetry #DAS

#SSA26 Jade Kessinger is presenting: Monitoring Network and Station State of Health with Grafana #Seismology #ComputerScience

#SSA26 Jessie Saunders is presenting: Stress Testing ShakeAlert Using the 2023 M7.7 Kahramanmaras Earthquake Sequence, Turkiye #Seismology #ShakeAlert #EEW

#SSA26 Qiushi Zhai is presenting: Toward Operational Earthquake Early Warning Using DAS Observations and Finder Algorithm: A Case Study in Southern California #Seismology #DAS #ShakeAlert #EEW

#SSA26 Allen Husker is presenting: The 2017 Mw 8.2 Mexican earthquake jumped from a normal outer-rise fault onto the megathrust interface. #Seismology #EarthquakeScience

#SSA26 Later today Yaozhong Shi is presenting: Large-scale 3D Ground-motion Synthesis With Physics-inspired Latent Operator Flow Matching #Seismology

#SSA26 Claude Felizardo and Jessie Saunders are presenting: Testing cloud-based resiliency options for the U.S. ShakeAlert earthquake early warning system #EEW @ShakeAlert #Seismology

#SSA26 is off to a good start! We highlight a few research efforts on here when SeismoLab and SCSN members submit their info, but there is a much larger presence at the meeting presenting, discussing, and making opportunities for future collaboration! Here is a small sample from day 1!

#SSA26 Today and tomorrow Gabrielle Tepp presents Evaluation of Distributed Acoustic Sensing Phase Pick Quality and Performance for Operational Earthquake Monitoring -- and Performance of the Deep-learning Phase Picker Phasenet on Magnitude 3+ Earthquakes in Southern California. #Seismology #DAS

#SSA26 Today Joann Stock presented: Updating Venus’ Predicted Seismicity Using New Global Wrinkle Ridge Map Generated Using Machine Learning #Seismology #Planetaryphysics #Venus

#SSA26 Igor Stubailo is presenting: Comparing Verizon and AT&T FirstNet Latency During the 2026 Rose Parade #telemetry #SCSN #Seismology

#SSA26 Ryan Tam presents Seismology as a Service at SCSN: portable product generation using service-oriented architecture and cloud computing for seismic workflows. #Seismology #CloudComputing #SCSN #Poster

#SSA26 Recent Innovations and Improvements for Real-time Operations at SCSN: Incorporating Machine Learning to Improve Monitoring Rayo Bhadha highlights ongoing upgrades to real-time operations and ML integration at the Southern California Seismic Network. #Seismology #SCSN #Poster

M3.5 24km SW of #Maricopa, CA, #SouthernCalifornia #Earthquake confirmed valid. Updated analysis coming soon @ www.scsn.org/index.php/earthquakes/latest-earthquake-information/

#SSA26 The Seismological Society of America Annual Meeting is here this week in Pasadena! With so many from the SeismoLab and SCSN participating in talks, poster sessions, and events, it's a busy week! Keep an eye out, we'll be sharing highlights throughout! meetings.seismosoc.org/am-program/

As Artemis II made its reentry and splashdown last Friday, the Seismo Lab took a moment to watch. We may spend our days monitoring the Earth and how it moves, but we’re just as inspired by milestones beyond it, celebrating the science and accomplishments that connect and fascinate us all.

This week the CA Seismic Safety Commission Advisory Board Meeting was held at Caltech. The SSC works with federal, state, and local agencies to support earthquake preparedness, mitigation, response, and recovery. The Seismo Lab and SCSN are glad to be a part of this vital initiative! buff.ly/M4euFcQ

#FieldPhotoFriday A recent trip out to the Lebec area offered some great views while the crew upgraded an old radio, datalogger, and batteries. Glad they made it out there before the temperature really starts going up! (and I'm sure they are too)

@EQHistory 16 years ago (yesterday) The M7.2 El Mayor-Cucapah earthquake occurred on Easter Sunday. It didn't occur on a single fault though, but across a network of different fault structures near the CA/Baja/Mexico borders. buff.ly/E1Ksmvs

#FieldPhotoFriday Throwback to a sandy day near Barstow, one of many maintenance trips that keep our seismic network running! These pics may be from years ago, but the station is still going strong today after a recent upgrade and visit. Same site, new tech, and a more resilient network!

Caltech Seismo Lab was proud to support the Abilities Expo, helping connect our community with earthquake preparedness resources and the benefits of ShakeAlert Earthquake Early Warning. #ShakeAlert #Preparedness

Weekly Earthquake Stats: 22 Mar 2026 - 28 Mar 2026. There were 339 events this week ranging from M -0.17 to a M 4.11 near Ludlow. Check out our weekly playback map and visit www.scsn.org for detailed information. #earthquakes #seismology #SCSN #weeklystats @CaltechSeismo

#FieldPhotoFriday Another beautiful (though unseasonably warm) trip out to one of our stations near Porterville. The crew went out last week to replace a number of pieces of equipment and made some upgrades, as well as cleared up some water damage. Great work and nice to see data rolling in again!

Reminder: All local high school sophomores and juniors! The deadline to apply for the Caltech Earthquake Fellows program is coming up on March 31 at 11:59 PM. Don’t miss your chance to gain hands-on experience in earthquake science with the Seismo Lab! Apply now: buff.ly/giGMyZZ

Meet Alexis Sáez, a Seismo Lab Post-Doc who works on developing theoretical models to explain how slow and fast earthquakes initiate, propagate, and stop! #SeismoLabSpotlight buff.ly/fosBP9B

Weekly Earthquake Stats: 15 Mar 2026 - 21 Mar 2026. There were 329 events this week ranging from M -0.48 to 3.29. Check out our weekly playback map and visit www.scsn.org for detailed information. #earthquakes #seismology #SCSN #weeklystats @CaltechSeismo

#FieldPhotoFriday You'd think a trip to the mountains would help escape the heat, but that's not always the case here in SoCal! Even in the heat the SCSN field crew keeps the network running, no matter the elevation!

#FieldPhotoFriday We've shared plenty of remote stations, now how about one closer to home! The SCSN would not have the coverage and station density needed to rapidly locate and distribute earthquake alerts if not for our many installations right in some folks backyards!

#EQHistory: 3/10/1933 M6.4 Long Beach. This EQ destroyed several school buildings. Had it struck during school hours, the death toll would have been far higher. Just 30 days later, California passed the Field Act — one of the first US laws mandating seismic building standards. buff.ly/cKH6m49