Guthrie Creek Geology Part II - Russ Fault Zone

I penetrated deeper towards ground zero of the Russ Fault, which is positioned south of Guthrie Creek and north of Cape Mendocino. Unfortunately, I reached a point along the beach where cliffs rise straight out of the surf zone--the surf was too rough to walk around this point, so I will have to come back during the summer when the sea is flat and the tide is low if I want to reach the true location of the fault. Nevertheless, the geology on display became progressively more extreme the farther south I hiked along the beach. Massive--as in hundreds of feet massive--blocks of hardened clayish stone have been thrusted high above the beach. These giant blocks of earth are likely being steeply thrusted upwards in response to their close proximity to the Cascadia Subduction Zone, Mendocino Fault Zone, and San Andreas Fault. This area usually experiences an earthquake, on the order of magnitude 4 or 5, every one to three months. Like anyone else, I enjoy a good earthquake from time to time. However, I was climbing over pieces of crust that clearly had been thrusted up out of the ground during the recent geological past. Thus, fearing that the 30 year return interval for a M6.0-M7.0 might verify that second, I believe I was probably muttering under my breath "not now, not now, not now."...definitely an eerie feeling knowing that I could be knocked up into the air any second if the Earth decided to move.

See the pictures below for some extreme examples of anticline folding and steeply angled blocks of earth, all of which dip toward the north.

Coast Guard Field Training Exercise

My NWS Eureka colleagues and I attended a Coast Guard Field Training Exercise on April 17, 2019 at the Samoa Airport west of Eureka, CA. We arrived at 8 am, watched Coast Guard, California Highway Patrol, and CalFire helicopters land; and then proceeded through a field training briefing, in which I gave a weather summary for all the participants. The highlight of the exercise was watching the Coast Guard helicopter team retrieve mock injured parties from the ground via assistance from local firefighters, who participated in order to familiarize themselves with helicopter assisted rescue operations.

Guthrie Creek Geology

The beach leading south from Guthrie Creek, which is accessed via a steep trail located off of Centerville Road in Humboldt County CA, displays incredible evidence of thrust faulting. Gigantic slabs of sand-stone'ish material have been thrusted hundreds of feet into the air. And the erosive wave action from the ocean hasn't had time to break these huge blocks of solid sand down even though the upwarped material extends straight up out of the ocean's edge. There are several thrust faults running more or less east-southeast to west-northwest, parallel to the nearby San Andreas Fault to the south. At low tide I hope to travel farther south along the beach and explore the remainder of this geologically active portion of Humboldt County.

Giants slabs of solidified sand are being thrusted upwards at a steep angle near Guthrie Creek.

Looking south toward Cape Mendocino and the Mendocino Triple Junction, where the San Andreas Fault, the Cascadia Subduction Zone, and the Mendocino Fault Zone all converge.

Trail south of Centerville Beach slowly sliding off into the ocean.

Sand bluffs rising high above Centerville Beach.