5.1 Magnitude Earthquake Rattles the Bay Area Transcript

Good evening. We got shook. Our biggest earthquake in eight years, a 5.1 magnitude with at least four aftershocks.

Raj the question now, what comes next? Right? And did the early warning system work as promised? NBC Bay area Stephanie Magallon begins our coverage in Morgan Hill, where Stephanie many are wondering tonight, if the South Bay will keep shaking?

Right. Well, first of all, I heard from several people who say they felt the shake in San Francisco, Alameda, and even in Salinas, and well here in downtown Morgan Hill, several of these business owners tell me that they were just opening up when the floor and ground started shaking.

(00:45)
We heard it rumble, classrooms shook, and many across the Bay area ran for cover.

We got scary. And I look around and I just saw the plants moving.

Here in downtown Morgan Hill, business owners and customers say they felt as if they were at the epicenter of the quake.

Like turbulence in an airplane. Really. It was a big one for me don’t know, the biggest that I ever had.

Deeper into the city, we found a family who says the 5.1 magnitude jolt was intense enough to cause this.

It knocked a whole mirror over and all my perfume bottles were underneath. And obviously the mirror’s broken, probably all my perfume bottles as well.

Apart from the scare it caused, we know Tuesday’s earthquake came from the Calaveras Fault, which runs through San Jose. Seismologists say that fault is a part of the San Andreas system.

The southern part where this earthquake happened, creeps. It means it sometimes moves without any earthquakes at all. And then you have some of these smaller ones. The largest we’ve ever seen on the Southern Calaveras is the 6.2 in Morgan Hill.

Dr. Lucy Jones says, the last time we saw a shake this big on the Calaveras Fault was in 2014, a 6.0 magnitude quake in Napa. Tuesday’s rattle only reached a magnitude of 5.1, but left many on alert.

Get out of the doorway.

Especially after feeling aftershocks with magnitudes as high as 3.6.

I was very scared, and I think just because of Loma Prieta, just waiting for it to keep going, not knowing if it was going to stop or not.

Many here say they’re feeling a bit anxious, I want to know if another big one’s going to hit us tonight or tomorrow. Well, Dr. Jones says that that’s not likely of anything, we’ll see two or three small ones within the next day or two. Live in Morgan Hill, I’m Stephanie Magallon. Back to you.

Stephanie, thank you. Yeah, less than a 4% chance at that point. Now, one of our viewers, Jack sent us this video. He was inside a classroom in San Francisco. You can see that artwork there, kind of bouncing around. Regardless where you were today, there’s a good chance you felt it. Marin County, Oakland, Fresno, and down to Monterey and Salinas.

All right, Chief Meteorologist, Jeff Ranieri has been busy tracking the series of aftershocks. Jeff, what are you seeing at the late hour?

Well, we haven’t really seen anything big over the past few hours. Well, take a look at that and you can see that 5.1 earthquake here with the epicenter located right in near Mount Hamilton in that mountainous area. And some of you may be wondering, okay, we had this eye-popping 5.1, and why wasn’t the damage worse? Well, it’s all about the topography where this was located. Those mountains actually helped to absorb a little bit of that energy, and that definitely could be why the South Bay didn’t see that shaking as intense. Now, a closer look here at those aftershocks and you can see a 2.9 today just after the initial one, we had a 2.9 at 11:47, a 3.5 at 3:08, and then a 2.8 at 5:20 tonight. So when you put this on the scale of things, a 5 magnitude quake is considered moderate, about 1500 of them per year, that’s equivalent to 1 million pounds of explosives. So a lot of force, a lot of energy with that.

(04:00)
On the shake map here, we got into some of this blue, little bit of that purple color, that’s considered light to moderate. Again, we’ve seen earthquakes that are lower in intensity, but they did bring us more violent shaking, it’s all about where that is located. So, on that Mercalli Shake scale, you can see we’re right in that light to moderate range, which did move some objects off of some locations. But other than that, it wasn’t really too bad for us. All right, we’re back with that full weather update, coming up in about 15 minutes.

All right, Jeff, thanks so much. Not so bad when it came to transportation as well, it was impacted by the earthquake, but service was up and running within minutes. Bart trains were held for five minutes after the quake hit as a precaution for any aftershocks. After that, they released trains at lower speeds. There were some minor delays of about 15 minutes, but things were back on track shortly after. And delays were also minor for VTA service. Trains were delayed for about five minutes for inspections, no damage or injuries. So service return to normal shortly after. And this quake comes as the Anderson Dam is in the midst of a major seismic retrofit. Our skyranger was overhead in Morgan Hill. Because of the retrofit project, the reservoir is only at 3% of its normal water levels. The project is supposed to bolster the 70-year old dam, so it can withstand a major earthquake. It’s expected to be completed by the middle of 2024, at a cost of $1.2 billion.

Here’s one of the big questions now. Were you one of the 95,000 people who got that early warning alert on your phone? This is either an automatic alert on your Android or through a free MyShake app on your iPhone. Many got the alert seconds before the quake hit. A lot of people farther away from the epicenter say they got a heads-up even as much as 10 seconds of notice. The people behind the MyShake app, which is based on, they’re based in Berkeley, did it work as planned today? The Director of the Berkeley Seismology Lab says, yes. But keep in mind, this system is not an earthquake predictor. Rather, it quickly detects the shaking where it originated, then it processes that information, and sends it out. Closer to the epicenter in San Jose, the alert might have arrived while things were actually shaking. But for example, in Oakland, Pleasanton, and Marine County, people likely receive the notifications before the quake reach them. And when the big one hits, a few seconds could be life saving.

So we know from the Loma Prieta earthquake, for example, also from the Northridge earthquake, that about half of the injuries in these big earthquakes, because either people fall over, or because things fall on people, things fall out of the bookcase, of the bookshelves, for example, behind me. And so if everybody gets a warning, and if everybody drops, covers and holds on, then we’re going to reduce the number of injuries in a very significant way.

How adds that his lab and USGS are still trying to determine who to target with these alerts. Everyone who will feel the shake or just those who will feel it, where it’s the most intense. Right now, they’re receiving a lot of feedback from the community and the public, and early indications show, if people feel it at any degree, they want those alerts.

Yeah. Raj, as we mentioned, this is the strongest earthquake in the Bay Area, the Bay Area I’ve seen in years, the strongest since the Napa quake in 2014. I remember the 6.0 magnitude quake struck in the middle of the night along the West Napa fault. One person died, dozens were injured. In October 2007, a 5.6 magnitude quake shook the San Jose area. It struck on the Calaveras Fault around eight o’clock. There was no major damage reported there. Of course, the largest and most destructive quake was the 1989 Loma Prieta earthquake. The 6.9 magnitude quake killed more than 60 people, left thousands hurt. The Cypress Freeway structure, and part of the Bay Bridge collapsed. If you ever feel shaking and want to know exactly how strong it was, make sure to check our quack tracker, nbcbayarea.com/quacktracker.