Posted on 02/12/2017 4:26:47 PM PST by janetjanet998
Edited on 02/12/2017 9:33:58 PM PST by Admin Moderator. [history]
The Oroville Dam is the highest in the nation.
San Joaquin River in Fresno is at flood stage. This is coming out of Friant Dam and per the map I saw, the river travels north to junction with the American and Sacramento rivers into the Delta.
https://cdec.water.ca.gov/river/rivcond.html
Merced county rivers also flooding.
Wrong link above. That shows you all the rivers in the state.
Here is the warning for the San Joaquin river
https://www.wunderground.com/US/CA/093.html
“I wouldn’t panic,” said Ogden. “But if I was one of those folks, I’d make sure there was an emergency plan in place for whatever dam you’re near.”
http://abc30.com/news/california-dams-lagging-behind-inspection-schedules/1755162/
Re: M1.0 event: Geologists haven’t indicated it was a blast. But due to it being tiny, deciphering the waveform for a blast at this location could have been assumed to be a quake. The depth of -0.03km is referenced to Mean Sea Level. The elevation of the surface at this location is around 291-310 feet (-0.0946km up from MSL*). Satellite maps of the location doesn’t indicate an active quarry... So nothing to confirm a “Controlled Blast”.
*note: a negative sign on the depth is upwards from 0.0 MSL. 1.6km depth of the 0.8 magnitude 2nd quake is 1.6km below MSL (this can be eliminated as a “controlled blast”.
Md0.99 Northern California
Event Summary
Date/Time
(UTC) 2017-02-14 10:56:01 UTC
(21 hours, 40 minutes ago)
Location Northern California
Magnitude Md 0.99
Latitude 39.541833° N
Longitude 121.509833° W
Depth -0.03 km
Depth -0.03 km
Surface -0.0946km
About 212 feet below the surface
Feds, Calif. disagree on seismic safety of U.S. tallest dam
Published 9 December 2013
(snip)
The Sacramento Bee reports that the 2010 inspection, conducted by consultants working for the Federal Energy Regulatory Commission (FERC), found no significant flaws in the dam itself. Inspectors recommended the earthquake safety assessment based on recent information about earthquake hazards in the vicinity of the dam.
The California Department of Water Resources (DWR) has no plans to conduct the assessment due to what the department considers to be an “unjustified expense,” but requests by state and federal regulators may force an assessment.
(snip)
Ronald Stork, a senior policy advocate at Friends of the River,noted that the Oroville Dam exhibits a case of reservoir-induced seismicity. In such a case, the reservoir itself can cause earthquakes due to the weight of water stored behind the dam being large enough to shift the earth’s crust. Studies have documented the case at Oroville. “A dam with a whole lot of shaking going on … does seem to be something you need to be really careful about,” said Stork, who monitors dam regulation across the state. “You lose a 3.5million acre-foot reservoir — the tallest in the United States — and that could cause a whole mess of downstream trouble.”
It looks like a dry creek bed at that lat lon
0.8 2017/02/14 02:39:52 39.547N 121.487W 1.6 4 km ( 3 mi) NNW of Oroville East, CA
this is really not good.
See the image in Post 991.
Yes, studies of dams in general have shown “weight reservoir-induced” causality to an increase of seismicity. However, in the case of Oroville dam the image doesn’t reveal a pattern of seismic events under or directly adjacent to the reservoir.
What is of a slight interest is a trending pattern (white dots) from the fault angle direction (see thin red line of a fault east of Palermo).
Thanks for that info. It’s worth keeping an eye on.
Here’s a useful link to monitor recent activity.
http://scedc.caltech.edu/recent/Quakes/quakes0.html
I wouldn’t be concerned about these two microquakes.
Only if a swarm of microquakes under/adjacent to the reservoir develop would there be something to start looking at.
There are far greater threats to the dam right now. Take your pick.
(Emergency spillway erosion damage, Main Spillway cavitation/hydraulic undercutting, elevated brown river levels back to the powerhouse [starting to saturate the toe or the bottom point “V” of the main dam fill structure], evidence of “bubbling” where water flowed/leaked under the Emergency spillway, strong jets of sidewall streams in the upper Main spillway [these streams are from strong flow water leakage under the upper Main spillway concrete & can create structural stress on the concrete slabs from voiding, etc).
Oh, and there is a significant chance of rain/snowmelt inflow again....
could it be the earth under and around the dam starting to shift?
Simple answer: no.
Only if a significant swarm of earthquakes - or - a large earthquake would there be an indication of a shift.
On the youtube interview with that Calhoun guy, he said something like “Yeah, something like this they have all the experts go look at it in the light of day - but it seems all the real crap goes down in the dead of night.”
Having worked nights on similar jobs - may God bless these workers and that they will keep their wits about them and stay safe.
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