California geologist, earthquake hazard scientist, Christian, frustrated Angels fan, and Oxford comma guy. Peace & Humpty-ness Forever! #SciComm (he/him)
Orange County, CA
Joined September 2009
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Hi, I’m Brian Olson—geologist, earthquake scientist, & SoCal resident. With 25+ years working in engineering geology, I tackle hazards like liquefaction, landslides, & active faults. Expect posts on quakes, geology, travel, Disneyland, & how the Angels break my heart. 🌍🏰⚾
Happy Statehood Day to California! ⛏️
Happy California Admission Day! On Sept 9, 1850, California became the 31st state, just two years after a discovery that changed everything: gold. The rush that followed grew CA's population from under 1,000 to nearly 100,000 in under two years. #AdmissionDay
ALT Front page of "The Californian" newspaper, published by B.R. Buckelew in San Francisco, dated March 15, 1848. A short item headlined "Gold Mine Found" reports that gold has been found in considerable quantities in the raceway of Captain Sutter's newly built sawmill on the American Fork, noting one person had already gathered thirty dollars' worth in a short time.
The “less than 2%” stat is technically true only under a narrow “national-average” framing that obscures how common slavery was where it existed. Slavery wasn’t the only injustice against Black Americans in US history, and accountability extends far beyond slaveowners.
This ignores: slavery was legal in ALL 13 original colonies until the early 1800s; “households” owned slaves, only counting male slaveowners is misleading; ignores that the US economic system overwhelmingly provided whites the opportunity to build enough wealth to own slaves.
Take it easy now! What is going on here? Two new M3.5s in Ontario (SW of the Rialto sequence) and then a M3.7 to the north near the San Andreas?? Let’s just turn the heat down a little, mkay? #earthquake
I was too sleepy last night to check that M3.7 near the San Andreas, but it shows a reverse faulting focal mechanism. Not the SAF, probably associated with the Cleghorn Fault (part of the North Frontal Fault System) that helps squeeze up the San Bernardino Mountains. #earthquake
ANNNNNDDDD we're BACK! The Rialto/Fontana earthquake sequence continues with a M3.5 aftershock this afternoon from Thursday's M4.3 quake. Overall, it still looks like it's on a fault related to the San Jacinto Fault zone (NW-trending). #earthquake
Looking at the @SCEC Community Fault Model, these quakes look like they are along the Lytle Creek strand of the San Jacinto Fault. (I should have checked this map earlier.) #earthquake
At first, I thought last week’s M4.3 earthquake near Rialto was linked to the NE-trending Fontana Seismic Lineament. But the aftershocks tell a different story. They outline a NW-trending fault, roughly parallel to the San Jacinto Fault. #earthquake
ALT Map of San Bernardino County showing earthquake epicenters from a recent M4.3 near Rialto. Yellow and orange dots mark aftershocks, forming a northwest-trending cluster subparallel to the San Jacinto Fault.
Tsunami waves still ringing around the Pacific. Crescent City tidal guage is still showing 6-8-foot wave heights. Port San Luis was seeing similar waves, but now they're in the 3-4 range. I would expect this to continue today, w/the possibility of a rogue surge in there. #tsunami
First tsunami waves are arriving on the east side of Kauai (Hawaii) at the Nawiliwili tide guage. #tsunami
WOW! Initial wave height in Hilo Bay is over 8-feet high! Hilo is no stranger to tsunami damage and seems to be the highest wave heights so far for any area of Hawaii. #tsunami
