Here is a little bit of information about the two local faults we have in Concord and Clayton, along with a few important links.
We’ll start with the Concord Fault. Although it’s not a major fault, it’s an active one. A lot of people don’t know about the Concord Fault, which runs north through Concord to Suisun Bay. There was a damaging 5.4 magnitude quake in 1955, and the USGS says there’s a chance it could produce a 6.7 magnitude quake before the year 2030.
Another fault in our area is the Clayton-Marsh Creek Fault. This fault is also active and continues to elevate Mt.Diablo.
According to the USGS maps pictured above, it looks like the Concord fault goes from above Crystyl Ranch into Lime Ridge, over Ygnacio, continues through Lime Ridge, over Treat Boulevard, down to Systron Drive and San Miguel, then it runs right under the BART tracks near Systron Drive and San Miguel Road, apparently you can see several cracks in the pavement that were created by the activity on the fault. It then goes through Downtown Concord and on to Pacheco. The red dot that says “Concord” is about where Concord BART is located (see top photo).
As for the Clayton fault, it goes in between Seeno’s house on the hill and the Concord Pavilion, then into the hills where it goes in several different directions from there.
The two earthquakes this week, a 4.5-magnitude and a 3.4-magnitude, were both on an unmapped fault, which is located near the Concord fault, according to the USGS.
For information on how to prepare for an earthquake, click HERE, and for information on the chances of a major earthquake in our area in the next 10-years, then click HERE.
18 comments
The USGS has been saying there’s going to be a big one since the 1960’s.
It’s the same as Chicken Little, “the sky is falling,” or the little boy who cried “wolf.” The public gets tired of it and the USGS lose credibility.
Who’s fault is that?
They are right. Earthquakes happen on geologic time scales, not human time scales. That means their best estimates might be off by a hundred years or more. But they absolutely will happen. The evidence is unequivocal. They have trenched the Haward fault down in Fremont, and identified and dated the last several surface ruptures (large quakes), and they happen fairly regularly, averaging every 150 years or so. It’s been about that long since the last one. Maybe the next one goes longer than average and doesn’t happen for 50 more years. Maybe 1906 changed the stress balance and is delaying it. But it will happen, 100 percent certain.
Its not my fault…
If you keep predicting something then when it happens you can say we told you. Saying there will be an earthquake on fault X between now and 2030 is as useful as predicting the sun will come up tomorrow morning.
Then Dawg, I suggest you pay no attention to their warnings. Don’t prepare at all. It will never happen anyway! But at least when it does, and you’re not prepared, you will then know who’s fault it is! 😉
LOL you said who’s “fault” is that 🤣
I know I should expect it right now, but it still amazes me how many people think that they’re smarter than all the scientists. They don’t have a degree or any formal education in the subject, but dag nabbit, they get by on common sense and gumption!
We live right on top of the Concord fault at San Miguel/Systron, across from the BART yard. We’ve known about it, but didn’t realize it could produce a quake as large as 6.7. That 4.5 in Pleasant Hill felt a lot bigger to us, though.
Isn’t that where they want to put the soccer stadium, too? Or closer to the police station, which is close to the fault too.
There is going to be a whole lot of shaking going on.
The Concord fault crosses Clayton Rd eastbound and Concord Blvd westbound just below Concord Ave, and was marked by offset curbs that the City has since fixed. The fault continues down Adobe St and passes under the Bayberry Convalescent Hospital.
I remember the quake of (I think about ’56) shook for a long time. We lived near 4-Corners, all the cabinets on one side of the kitchen opened and contents (cereal, etc) dumped to the middle of the floor. Grocery store shelves were swept clean. Downtown, the owner of the liquor store at the corner of Grant and Salvio squeegeed gallons or booze into the gutter.
I worked at Systron Donner. The Concord fault goes under a corner of the building. Luckily, we never had an earthquake during work hours.
Something to be aware of, much of downtown Walnut Creek and Pleasant Hill, have a water table this only 10 feet down or so. This is why you see so much “red zone” detailed in these areas on maps. Red zones very prone to liquefaction, the jelly like shaking of ground which can be so destructive in major quakes. A major quake on the Concord fault would probably leave much of our area homeless.
Unbelieveable how much lies along the Hayward Fault. That would be apocalyptic
There is also one under the Pitttsburg High School, not active but with all this shake up in the area who knows.
The proposed 18,000 seat soccer stadium would be built right on the fault line at Cowell and Galindo.
Maybe we can get the San Jose Earthquakes to play there.
When we were buying our house in Clayton 42 years ago (while we could still back out of the deal) I met with the city engineer to see where it was in relation to any of the faults. He said I was the first person to have ever asked the question. According to a seismic engineer at the time, the general rule was to be at least 1/4 mile from any branch of a minor fault to be reasonably safe, which we were.
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