USGS warns strong aftershock could follow Napa earthquake

Officials continue to collect information on Bay Area's largest earthquake since 1989

There is a 25 percent chance of a strong and potentially damaging aftershock in the next seven days following Sunday's 6.0-magnitude earthquake near American Canyon, U.S. Geological Survey officials said Monday.

The South Napa earthquake struck at 3:20 a.m. Sunday northwest of American Canyon, about seven miles below the earth's surface, USGS officials said. It was the strongest earthquake in the Bay Area since the 6.9-magnitude 1989 Loma Prieta earthquake that killed 63 people and injured 3,757. Sunday's earthquake moved the earth several inches along the West Napa Fault, the most seismically active fault mapped between the Rogers Creek Fault to the west and the Concord-Green Valley Fault to the east, according to the USGS.

A 5.0-magnitude quake in the Yountville area in 2000 happened on the same fault and also damaged Napa, while a 6.3-magnitude quake in the Mare Island area in 1898 was along the fault as well.

Most of the damage was concentrated in Napa, northwest of the epicenter, as the rupture sent most of the quake's energy in that direction.

Dozens of aftershocks recorded since then have also sent energy in that direction, USGS officials said.

Seismic researchers are continuing to collect information about the earthquake and are working to improve an early warning test system that alerted the USGS a quake was coming within five seconds and estimated its magnitude at 5.7 within three seconds, soon enough to provide warning to Berkeley, San Francisco and areas farther south.

City officials reported Monday morning that a total of 208 patients have been treated at Queen of the Valley Medical Center in Napa with 17 admitted. Most injuries are orthopedic, and many occurred when people were cleaning up their homes in the aftermath of the earthquake.

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1 person likes this
Posted by Resident
a resident of Another Palo Alto neighborhood
on Aug 25, 2014 at 4:37 pm

Like everyone else in the area, I have been watching the media give their saturation reports on this quake. It is definitely a wake up call for us living here.

At this stage, instead of hearing more and more reports on the damage, I would like to know a little more on what worked.

They said the early warning system in Berkeley gave a 10 second warning. Did that actually do any good? Did firehouses get a chance to open their automatic doors, etc.? Even with a 30 second warning, particularly in the middle of the night, can that make a difference?

Did neighborhood support groups kick in? I have heard a couple of reports of neighbors helping neighbors, but did the neighborhood organized groups manage to help in a way that official emergency responders were unable to do so?

Did people have their own emergency supplies or were they fully dependent on Red Cross type help? Did local return 911 calls give out any useful information? Did cell towers/phone lines/internet services manage to handle all the requirements?

Was there any need for rolls of cash, prevention of looting, hot food distribution and shelters for displaced people?

These are the things that can show us what works and what is a waste of time, the real lessons for preparedness

1 person likes this
Posted by Mark
a resident of Stanford
on Aug 25, 2014 at 10:07 pm


Please note that the Early Earthquake Warning system demonstrated by UC Berkeley is only a prototype system. It requires a lot more State/Federal funding before it can be used by a larger number of users, including the general public.

Having said that, Vallejo Fire Department apparently spent a lot of money investing in a private early warning system by a company called Seismic Warning Systems. This company's webpage claims that the system activated as designed, but I have not heard any actual verification from news stories that it actually did what it was supposed to do (i.e. alert firefighters, open bay doors, etc.) The company was pretty sketchy on the details so I am very curious if it actually worked or not.

I can tell you I have seen pictures of folks who evacuated from the Napa earthquake who had their own disaster kit, which was good to see. I also was impressed that residents at the trailer home park apparently shut off the gas after the earthquake when they realized there was a fire - that was the right thing to do.

I have yet to hear back on reports from the local Community Emergency Response Teams. It would appear that the Fire Department was able to handle most of the response since damage was focused in a smaller area (compared to Loma Prieta) and mutual aid was sufficient for the increased response needs. I know that several adjacent citizen community emergency response teams were on standby to assist, but did not need to be called in.

The Red Cross has 1 shelter in Napa that is still open with 9 clients staying there tonight (as reported by the Red Cross National Shelter System website). The Salvation Army has also been providing canteen services to first responders.

I think the bottom line is that while this was a serious earthquake, we should not kid ourselves: a more damaging, devastating disaster is always possible and everyone should take steps to ensure personal preparedness.

1 person likes this
Posted by Sea-Seelam Reddy
a resident of College Terrace
on Aug 25, 2014 at 10:23 pm

I hope we are all thinking about this.

I personally have been impacted by many earth quakes since I lived in California since 1977. My ex-wife's house was damaged during North Ridge earthquake in 1994.

So, I have taken all the heavy wall hangings (pictures) so they do not fall on me.

I have an earthquake kit; I have some water, Peanut Butter; etc.,

I hope the city agency can guide us on how to be prepared. We all need to be prepared to get through this.


1 person likes this
Posted by Sea-Seelam Reddy
a resident of College Terrace
on Aug 26, 2014 at 4:50 am

Dear citizens of Palo Alto we love!

I am not an earth quake triage expert:

We are at our own homes as we are the first that are impacted in our homes with our loved once.

- As we know these quakes occur different times; many at night and early morning or for that matter any time of the day.

- Please talk to your Earth Quake expert and be prepared.
- There is no need for panic. But, we need to be vigilant.
- We need to protect our children and elderly;

- Please keep in mind what we need to do if we do not have electric power even for few hours;- do we have batteries?
- Please keep an eye on everything as we know we can start early to triage.


1 person likes this
Posted by R
a resident of Menlo Park
on Aug 26, 2014 at 12:20 pm

I want to take a second and provide a few links to some websites about earthquake preparedness because there is far too much to mention here in terms of what we should all do and consider when trying to prepare (don't forget about pet supplies if you have pets and medications you may need for example).
There is also a link below to a guide FEMA put out for homeowners specifically, and you will need Adobe Reader to read that, but they provide a link to the free download in case someone doesn't have it already.

I hope these are helpful, and, IMHO, I do think it's everyone's responsibility to do all they possibly can to be prepared. There are never enough resources to go around when disaster strikes, and if the majority of people think they'll be taken care of if/when the worst happens, I shudder to think of the state we'll find ourselves in as that just won't be the case.

Web Link
Web Link
Web Link
Web Link
Web Link

1 person likes this
Posted by Sea-Seelam Reddy
a resident of College Terrace
on Aug 27, 2014 at 3:25 am

R in Menlo above

Thanks a million.
Great information.

Sorry, but further commenting on this topic has been closed.

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