Matt Springer has been giving presentations around San Francisco about home earthquake preparedness since 2008 (for more information about the presentation, go to his earthquake preparedness website). For those who cannot attend in person, a streaming version of the presentation is available online. This Quaketips blog is devoted to posts ranging from technical "how-to" articles to more philosophical "should-you" topics. New articles will be posted at most about once a month, so people who subscribe won't be subjected to lots of e-mail.

The suggestions contained in this website and in Matt Springer's presentations will substantially reduce the chances of an earthquake causing damage or injury, but cannot guarantee that problems will not still occur due to factors including but not limited to extreme seismic conditions, unexpected structural problems, bracing material flaws, or inadequate installation. This material is based on personal experience, research, and discussion with safety experts; Matt Springer does not have an official emergency management background other than standard community volunteer training. The information contained herein does not necessarily reflect the views of UCSF or the San Francisco Public Library.

Tuesday, December 27, 2022

The western US ShakeAlert system is loudly proclaiming its arrival (A Story of Three Alerts)

I was driving in San Francisco to an orchestra rehearsal about three months ago and listening to music on the car stereo from my iPhone, and then something unusual happened in the middle of the music: there was a jangling noise and a disembodied man’s voice said something like “Earthquake!  Drop, cover, and hold on.  Shaking expected.”  A MyShake app notification was on the screen saying something about a 5.0 in Sonoma County.  I thought that was odd because a 5.0 in Sonoma County would be unlikely to cause a problem in San Francisco, but I pulled over and turned off the car and waited to see what would happen.  And then a few seconds later, it happened!  The car moved!  It moved back and forth about 3 times... by a distance roughly the length of an ant.

This exciting experience, while “ant-iclimactic,” got me thinking about what would happen if a bunch of cell phones on stage and in the audience suddenly started blaring alarms in the middle of a concert, especially if followed merely by an ant-sized movement.  I contacted the folks over at UC Berkeley who administer MyShake (which taps into the ShakeAlert earthquake early warning system for the West Coast of the US), and asked why the alert had gone to a place with such little shaking.  They told me that actually, most of the complaints that they received were from people who did experience shaking and were not warned, so this gives you an idea of how hard it is to thread such a needle.  I wrote about this issue in an earlier Quaketips post in late 2019.

A month later, I got another MyShake alert on my phone while at home in the late morning, a loud noise, which startled me quite a bit, about a 5.1 down near San Jose.  Several seconds after that, we indeed started moving (enough to be unnerving), and thanks to the alert, I was expecting it and didn’t have to waste time going through the “is that really an earthquake?” routine.  Between already knowing it was just a 5, and feeling the mild beginning of the shaking, I actually did not get under my desk but I was ready to do that if it got worse, and I already knew there were no lit stove burners or candles, etc.  That alert was really worthwhile.

Well, just a few nights ago, they had a nice medium-large one (6.4) up in Humboldt County, about 250 miles north of San Francisco.  A BUNCH of people in Northern California got a MyShake alert about this one, which actually caused a lot of damage up there.  Down here in San Francisco, we got the alert and depending on where people were and what they were doing, we either felt a slight shaking or no shaking, again making people ask why we got an alert for a quake that was so far away.  Here’s an interesting fact: I inquired with the Berkeley people again and was told that the app is supposed to send an alert for any California/Oregon/Washington quake over 4.5 on the Richter Scale to the zone that is expected to experience shaking at level 3 of the Modified Mercalli Intensity scale (weak shaking), and San Francisco might not have gotten an alert for this 6.4 in Humboldt except that the quake was initially estimated at a 6.6, which would have shaken a larger area.  (Because this is a log scale, the difference between a 6.4 quake and a 6.6 quake is actually pretty substantial.)  The alert went out on that basis so it overestimated who should get it.

This is a great example of one of the unavoidable ironies of such a system: because the alerts are based on shaking at the epicenter that then radiates outwards to where most of the alert recipients are, those who are at the epicenter where the quake is strongest and thus are most in need of an early warning will not be the ones who get the warning early.  And indeed, there were reports on the news about people in the strongest shaking area saying they got the alert after the quake was already in progress, which must have felt like a Homer Simpson “D’oh!” moment but you can see why it’s a natural part of the system.  Between the people who get shaken the most without warning, and the people who barely feel the shaking and have an early warning a nice long time beforehand, is the "sweet spot” of the people who will benefit from the system the most: those who are close enough to the epicenter to experience substantial shaking but far enough from the epicenter to not experience shaking until several seconds after the warning is received.

At any rate, I don’t think anyone would argue that having an early warning system is not worth the occasional “false alarm” for some locations.  Still, I continue to be concerned about the two biggest problems that I can see resulting from such overestimated alerts: harm and complacency.  

By harm, I mean that having one’s phone make a noise even when set on “do not disturb,” or having many phones make those noises, can create problems and hazards that would be moot if an actual earthquake was occurring but will be trouble if there’s no quake.  For example, as I mentioned in my previous article about ShakeAlert and MyShake, a bunch of phones squealing all of a sudden during a performance of acrobats doing death-defying stunts could make them no longer death-defying if someone gets startled and doesn’t successfully grab something they are supposed to grab.  Less consequential but more likely, if my phone goes off while I’m in the audience at an orchestra concert or ballet (not followed by a quake), I will be universally hated by everyone (except for anyone else whose phone went off and is also being universally hated).  And if my phone goes off while I am PLAYING in an orchestra concert with no quake, that’s an absolutely unacceptable situation and I’m actually concerned about that.  Here’s one more: having your phone go off during some little kid’s first-ever piano recital; think about it!

I typically set my phone to “Do Not Disturb” when playing a concert, but now I may have to also turn off the sound of Emergency Alerts on my iPhone (currently for iOS 15, Settings -> Notifications -> Government Alerts (it’s all the way at the bottom) -> turn “Always Play Sound” to off), or resort to turning off the phone altogether, at times like that.  (One caveat, this seems to change with every OS update, so I’ll have to figure it out over and over again, or just turn the phone off.)

“Above all, do no harm” does not apply here, as it is incompatible with “protect as many people as possible from dangerous effects of earthquakes.”

The other problem is complacency: if MyShake keeps interrupting people and possibly even causing some of the hassles described above, with hardly any shaking, lots of people will simply delete the app if they don’t have the ability to turn it off when in do-not-disturb mode.

Here’s one suggestion about how to find a middle ground, at least for those with iPhones.  Remember that there’s a difference between “notifications” and “alerts,” whereby notifications are after-the-fact news flashes that tell you when a quake above your magnitude of choice has occurred in a geographic location of your choice (a nice recent added capability), whereas alerts are the actual early warnings that tell you the ground might shake soon.  Currently, the alerts are themselves of two flavors: those that go to your phone’s location and those that go to your default “Home Base.”  If you have location services turned on, then wherever you are, MyShake will know where the phone is and will alert you if the phone is in a region that is expected to shake.  On the other hand, your Home Base is a location that you set manually so that if that region is expected to shake, your phone will get the alert, regardless of whether the phone is in that location or elsewhere.  However, you don’t have to set a Home Base location.  If you only want to be alerted if your current location is about to shake, and don’t want the early warning if your home base location is about to shake if you are not there, then leave the Home Base location unset (or delete it if you have one already).  Your phone will still sound the alert if you are in that location right before a quake there (assuming location services are on), and will sound the alert if you are somewhere else right before a quake in that place, but won’t sound the alert if your home is about to shake but your current location is not.

This solves some of the problem, because if my phone sounds the alert when my current location is expecting shaking, then presumably, lots of phones in the area will sound the alert as well and interrupting the concert won’t be MY fault.  However, with my Home Base set for San Francisco, if it comes to pass that San Francisco and the area north of it is about to shake, and my phone and I are in San Jose 50 miles to the south where shaking is barely felt (or for that matter, if I’m in Los Angeles or New York or Paris), then I’d be the only one causing a disturbance completely irrelevant to everyone else within earshot.  Not having a Home Base set at least prevents against this undesirable situation.

However, there does not seem to be a feasible way to prevent occurrences when lots of phones in a US West Coast audience will squeal about a coming local earthquake, either followed by significant shaking or not.  I suggest that orchestra and choral conductors, theater and ballet directors, and directors of acrobatic shows like Cirque du Soleil, plan ahead and decide what their response will be when the chorus of phones in the audience starts squealing.

Oh, and secret agents who are sneaking around hiding from the bad guys should probably turn off those emergency alerts also.  James Bond might like things shaken, but he wouldn’t want his phone to cause a stir.

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