Southern California earthquakes of 6.4 on July 4th and 7.1 July 5th

[Mr Quatro]

I was in LA for the 1994 earthquake on Martin Luther King's birthday and it was terrible all of Hollywood was dark with no power traffic lights out
with everyone in shock and these two earthquakes are even bigger than that one.

I wonder if an even bigger one is coming


12 of the worst earthquakes to hit Southern California

https://www.recordnet.com/news/20190...INL_z4VwpBNWq8

[Sailor Steve]

I was living in Westwood, California, the home of UCLA, when the 1971 San Fernando quake rocked L.A. I was awoken pre-dawn to the sound of my dresser banging against the wall. That was my only clue at the time.

[mapuc]

It have been on the news here and I'm thinking the same

Are these two earthquake a taste of what is coming a big one ?

Markus

[fireftr18]

Prayers for those in California. Achtung, have you had any effect from it?

[Aktungbby]

I WAS A PRINCIPLE APPRAISER IN THE SANTA CRUZ MOUNTAINS WHEN THIS BIG ONE HIT-WRECKING MY APARTMENT....

The 1989 Loma Prieta earthquake occurred in Northern California on October 17 at 5:04 p.m. local time (1989-10-18 00:04 UTC). The shock was centered in The Forest of Nisene Marks State Park approximately 10 mi (16 km) northeast of Santa Cruz on a section of the San Andreas Fault System and was named for the nearby Loma Prieta Peak in the Santa Cruz Mountains. With an Mw magnitude of 6.9 and a maximum Modified Mercalli intensity of IX (Violent), the shock was responsible for 63 deaths and 3,757 injuries. The Loma Prieta segment of the San Andreas Fault System had been relatively inactive since the 1906 San Francisco earthquake (to the degree that it was designated a seismic gap) until two moderate foreshocks occurred in June 1988 and again in August 1989.
Damage was heavy in Santa Cruz County and less so to the south in Monterey County, but effects extended well to the north into the San Francisco Bay Area, both on the San Francisco Peninsula and across the bay in Oakland. No surface faulting occurred, though a large number of other ground failures and landslides were present, especially in the Summit area of the Santa Cruz Mountains. Liquefaction was also a significant issue, especially in the heavily damaged Marina District of San Francisco, but its effects were also seen in the East Bay, and near the shore of Monterey Bay, where a non-destructive tsunami was also observed.
Because it happened during a national live broadcast of the 1989 World Series, it is sometimes referred to as the "World Series earthquake".

https://en.wikipedia.org/wiki/1989_Loma_Prieta_earthquake MY APPRAISAL FILES WERE USED BY FEMA TO HELPS PEOPLE DEVASTATED AS I HAD THE ONLY PHOTOS OF THE HOMES PREVIOUS TO THEIR DESTRUCTION. SINCE MOVING TO NAPA, I'VE BEEN IN TWO EARTHQUAKES ONE OF WHICH DESTROYED MY CHIMNEY IN 2000 AND A WHOLE LOTTA CHINA DISHES AND SHEETROCK WALLS. https://en.wikipedia.org/wiki/2000_Yountville_earthquake , EPICENTERED 500 YARDS NW FROM MY HOME IN THE PREVIOUSLY UNDETECTED 'WEST NAPA FAULT'...NOW WE HAVE QUAKE LATCHES ON ALL CABINETS AN KEEP THE GOOD STUFF LOW TO THE FLOOR. THE BBQ IS ALWAYS READY AS THE NEIGHBORS ALL WANT COFFEE FIRST THING BEFORE ROLLING UP SLEEVES TO RESTORE NORMALCY. THE MOST RECENT ONE: 2014; WAS 10 MILES SOUTH AND DEEP ALONG THE SAME NAPA FAULT AND REALLY CAUSED DAMAGE:

Total damage in the southern Napa Valley and Vallejo areas was in the range of $362 million to 1 billion, with one person killed and 200 injured. Other aspects of the event included an experimental earthquake warning system that alerted seismologists several seconds before the damaging shear waves arrived, temporary changes in springs and wells, and the potential for postseismicfault creep.

https://en.wikipedia.org/wiki/2014_South_Napa_earthquake THROW IN A COUPLE OF MAJOR FIRE STORMS ...THIS IS STILL THE BEST PLACE ON EARTH TO LIVE BBY! I REGARD THE LITTLE QUAKES AND AFTER-SHOCKS AS POSSIBLY A GOOD THING AS IT MIGHT ALLEVIATE STRESS ALONG THE TECTONIC PLATES ALONG THE MAJOR SAN ANDREAS FAULT WHICH IS EXPECTED TO CAUSE 'THE BIG ONE'! THAT SAID, THERE ARE EXPERTS WHO DISAGREE WITH MY POSITIVE THINKING

They noted that the new observation is significant because it uncovers a new type of fault motion and earthquake-triggering mechanism, which is not accounted for in current models of earthquake hazards used for California.
As Shirzaei explained:

Based on our observations, we believe that seismic hazard in California is something that varies over time and is probably higher than what people have thought up to now.

He added that accurate estimates of this varying hazard are essential to include in operational earthquake-forecasting Bottom line: New research from Arizona State University shows that movements along the central section of the San Andreas fault haven’t been smooth and steady, as previously thought. It also shows that episodic slow earthquakes along the central San Andreas don’t relieve stress; instead, they cause stress, which may trigger large, destructive earthquakes.

FOOTNOTE TO HISTORY: THE ELECTED ASSESSOR-OF-THE-COUNTY HAD PREVIOUSLY TOLD ME I WAS OVER-QUALIFIED TO BE AN ASSISTANT ASSESSOR WHEN I HAD JUST MOVED TO NAPA. BUT AFTER THE THE 2000 QUAKE, AND STILL COVERED IN DUST-IN T-SHIRT, SANDALS AND CUTOFFS, I STROLLED INTO THE HASTILY ESTABLISHED FEMA OFFICE AND ENCOUNTERD THE ASSESSOR... STANDING SOMEWHAT IN AWE OF THE SAME FEMA PEOPLE, OUT OF WASHINTON D.C., THAT I'D DEALT WITH IN BORROWING MY FILES FOR QUAKES AND MAJOR FIRES OVER 15 YEARS. IN (MY) REFLECTING ALOUD THAT 'WE HAD A LOT OF ELDERLY AND NON-ENGLISH SPEAKERS WHO DIDN'T KNOW THEIR DAMAGES' THE HEAD FEMA HONCHO IMMEDIATELY RESPONDED ''I THINK YOU'RE RIGHT WE'LL STAY HERE A YEAR"...THE ASSESSOR LOOKED AT ME IN PLEASANT SHOCK...BUT I HAD SOLVED HIS IMMEDIATE PROBLEM! SOME YEARS LATER, HE CAUGHT UP WITH ME ON A SECURITY ASSIGNMENT AND STATED THERE WAS AN ON-CALL ASSESSOR POSITION ON CRAIGS LIST....WOULD I PLEASE FILL OUT THE APPLICATION....I DECLINED!

[vienna]

Here in Hollywood, we are about 150 miles away from the epicenters of the quakes from the past two days, but we definitely felt them, and some of the aftershocks. I'm originally from San Francisco and, in Northern CA, people are used to earthquakes; I usually don't give much attention to anything under a 5 on the Richter Scale. On the morning of July 4th, I was sitting down on an office chair in my home; I had minutes earlier nearly tipped over the chair with me on it when I had dropped something on the floor and awkwardly tried to lean over and pick it up; when the 6.4 hit, at first I thought the chair was slipping away again, but I immediately realized every thing else in the room was jerking about; the felling was not a hard jolt or jolts, but more like being in a small boat when a larger boat's wake hits it, a sort of shifting side to side and up and down motion; this went on for a good thirty seconds and I became a bit concerned about two-thirds of the way through we might be having a repeat of the Northridge earthquake of 1994. Interestingly, there was no sound of any kind, such as accompanies good-sized earthquakes. After it stopped, I knew whatever it was, it was a really strong quake and I turned on the TV to see if there were any reports about location, damage, etc. I flipped around the dial a few times and saw nothing other than the scheduled; apparently, the news personnel at the stations had ducked and covered at the time of the quake and it took sveral minutes for them to get it together. The magnitude was given as 6.4, the largest in SOCal in 20 years:





Early the next morning, July 5th, I woke up, for no reason, at a couple of minutes past 4:00 am; I lay there for a bit wondering why I was awake and trying to go back to sleep when the 5.4 aftershock hit, with the same 'bobbing boat' effect; that quake was about 15 seconds in length and, after briefly checking the TV news to see if there was anything to be concerned about, I went back to sleep...


Last night, I was in bed, watching TV, when the 7.1 quake hit; at first I thought it was another after shock, but it built up steam and really began to move, with the same 'bobbing boat' motion and lasting at least 30 seconds; almost immediately, the TV stations cut to news coverage and were in a better position to report since they still had news crews at the location(s) in the Ridgecrest epicenter area; some of the reporters on the scene, who had just moments before been at the center of the quake looked a bit apprehensive as they made their reports...


Ridgecrest is about 150 miles away fro LA, so for us to feel the quake that sharply give you an idea of how really powerful the quakes have been. The best news is that there have been no fatalities or major injuries and damage has been at a minimum considering the size of the quakes; the area is on the edge of the desert area in the East and is the home of the China Lake Naval Weapons Station, a major defense installation:


Naval Air Weapons Station China Lake --

https://en.wikipedia.org/wiki/Naval_...ion_China_Lake


The base is now closed due to the quakes, pending assessment:


Navy’s China Lake base closed, assessing damage after earthquakes --

https://www.stripes.com/news/us/navy...uakes-1.589148


Two factors of good fortune serving to minimize damage at the epicenter have been the fact the bedrock in the area is solid granite and able to endure shock with minimal fracturing and the fact most of the heavily populated areas are of recent development and the vast majority of the structures are low-rise and built to codes put in place after other devastating quakes in other ares of CA. If the same quakes had occurred in more densely populated areas with larger numbers of pre-code structures, the results would have been far less fortunate...


One of the things being talked about here in LA in the wake of the quakes has been a 'quake early-warning' system initiated in recent years and in early use via cellphone app(s). Basically, when sensors at the quake site detect a quake, a warning notification is sent to the app(s) alerting the users of possible ripple shocks headed their way; the amount of time of the warning varies by distance from the sensors; in LA, the time margin for the recent quakes was about 15 seconds. This may not sound like much, but there was a practical impromptu demonstration last night when, during a press conference at CalTech (Calif. Institute of Technology, 'home' to Sheldon Cooper) in Pasadena adjacent to LA,, a sensor alarm went off signalling an approximately 5.0 aftershock; the speaker noted the alarm and all assembled waited to see how long it took for the quake's shock to hit Pasadea; after 15 seconds the shock was felt; while watching this and waiting, 15 seconds was a surprisingly "long" time; I could have easily left my building and been outside away from any danger if I so chose; I may have to add that app to my cell (and I do hate to use apps)...


I have been through about a half-dozen major, damaging quakes since I came here to LA in 1970 and this is the first time in my life I have ever felt/seen a situation where what would be considered by accepted metrics as a major quake (6.4 magnitude) become 'demoted to a 'pre-shock' by a later quake (7.1 magnitude); it has always been major shock followed by diminishing after shocks; there are many, including myself, mulling over the possibility of yet larger shock to come and further 'demote' the current shocks...


@ mapuc: the Ridgecrest quakes are on 'small' faults in CA; the 'Big One' everyone is expecting and dreading would come from activity on the San Andreas Fault which is roughly 1,200 Km long and runs almost the entire length of CA:


San Andreas Fault --

https://en.wikipedia.org/wiki/San_Andreas_Fault


There have been past ruptures in areas of the fault, causing past major quakes, with the largest being The Great San Francisco Earthquake of 1906 which left 80% of the city in rubble and killed at least 3,000 people; there was a fire caused by effects of the Quake which consumed much of what was left of the city. We are still waiting for the 'Big One' on the San Andreas...








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[vienna]

Just heard on the local CBS newsradio station that NAWS China Lake appears to have sustained considerable damage and non-essential personnel have been ordered off the base. Being a military base involved in weapons development, information is closely held and ither than saying all waepons on base are fully secured, the Navy is not going into specifics about the nature or extent of any earthquake damage...









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[Buddahaid]

Well I didn't feel any of it at the Giant's game last night but my sister in Santa Barbara sure did. A friend in Walnut Creek (Concord) felt it though. Left the game in the fifth inning and went to Amichi's Pizza across from the ballpark and enjoyed some cheaper beer and New York style pizza while watching the game on video. Win! The ferry ride to Larkspur still took until 00:45 to dock. I love the 50 minute ferry ride from the park and feeling the swells when exposed to the full current from the Golden Gate. I expect Gojira to show every time.....

[Jimbuna]

Looked pretty bad here on the UK news....stay safe people.

[vienna]

The latest on the quakes in Kern County:

Ridgecrest, a city of about 29,000 persons, is still feeling swarms of aftershocks and is still dealing with cleanup. Massive support is being offered and provided by first responder units from other jurisdictions throughout CA and from out of state. Locally, it has been reported the evacuation of the NWAS China Lake, of which Ridgecrest is the main civilian area, is going to remain on minimal staffing for the foreseeable future; tis is an additional blow to Ridgecrest since approximately 85% of the economic life of the town is tied to the NWAS...

things are worse for the town of Trona, population about 1,900 persons, and about 20 miles from Ridgecrest. Trona is also on the epicenter's fault line and was hit even harder than Ridgecrest; the towns water system was severely damaged and there is no running water; electric power has been spotty and unreliable; many of the homes and buildings were so damaged, fearful residents have been sleeping outdoors. Its going to be a difficult recovery for Trona...

Originally Posted by Buddahaid

Well I didn't feel any of it at the Giant's game last night but my sister in Santa Barbara sure did. A friend in Walnut Creek (Concord) felt it though. Left the game in the fifth inning and went to Amichi's Pizza across from the ballpark and enjoyed some cheaper beer and New York style pizza while watching the game on video. Win! The ferry ride to Larkspur still took until 00:45 to dock. I love the 50 minute ferry ride from the park and feeling the swells when exposed to the full current from the Golden Gate. I expect Gojira to show every time.....

The 7.1 quake hit while the LA Dodgers were playing a home game and this is footage of what happened at the game:





The feeling of swells you mentioned was exactly what the earthquakes felt like here in LA. When I was a kid in SF, I used to got down to place near the base of the Golden Gate Bridge and watch boat and ships as they hit the waters of the Bay and the Pacific as they churned together as they met under the Bridge; it was an awesome sight to see a giant ship get tossed around by the remarkable forces of nature...








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[Platapus]

Earthquake


Continues to play ball.


'mericans

[vienna]

Many years ago, on the Johnny Carson Tonight Show, there was a guest (it might have been Joe Garagiola) who was discussing various sportscasters and mentioned a then well-known baseball play-by-play announcer with a reputation for being unflappable; the guest posited a scenario that might occur if a major emergency occurred during a game called by that announcer:


"...Bottom of the fourth... Jones at bat...He's been pretty quiet batting lately, maybe a slump... I've just been handed a news flash, windup, pitch, ball one...the Pentagon is reporting a radar contact on the Early Warniig System, Jones steps out of the box... NORAD says a large number of Soviet ICBMs have been tracked on route to the USA, Jones looks at a pitch, strike one... this inning is brought to you by Bud Beer, Milwaukee's finest... NORAD estimates the missiles will impact in 45 minutes, Jones hits a foul down the first base line, strike two... Hope we can get through the fifth-inning and save the win for the home team..."...








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