I received my first and, as yet, only earthquake warning on my smart phone this past September for a 4.3 earthquake here in Southern California.
It was an interesting fleeting experience. I was sitting on the couch, phone in hand, when it emitted an unusual fairly obnoxious noise. I glanced at the screen, saw the words earthquake and 4 something, and understood what was being conveyed sort of inchoately without making it explicit sense of it. My wife was sitting next to me reading so I turned to her and tried to show it to her but she remained absorbed in her reading.
Then the room jolted, rocked a little, and settled. The nice thing about the alert is I remained relaxed the whole time. Because the alert indicated the magnitude, I wasn't too worried about damage or personal injury.
Now if it had warned of a larger earthquake, like a 5 or 6, I imagine I would have been more panicked. Still, the warning would have been even more valuable in that case.
It was one of the more acute "Now this feels like living in the future" moments I've had recently.
I was once in my old Tokyo apartment on the 12th floor. I use an early earthquake warning app. It buzzed, telling me a 9.0 occurred in Tokyo bay and I have approximately 3 seconds before the very extreme shaking starts. I just sat down and thought "welp I'm dead".
It turned out to be a false alarm, triggered by something like a monitoring station being struck by lightning. I still have the screenshot of what the app looked like when it told me.
Yikes, that reminds me of the false ’we are all going to be bombed soon, this is not a test’ warning the people in Hawaii got… there should be penalties for false alarms like this.
In many cases there is some opportunity to validate information before it goes out. In others ... not so much.
Even a missile-launch alarm would typically have some opportunity to be assessed based on alert values (e.g., increasing or decreasing hostilities), and perhaps multiple sensor systems (boost-phase IR tracks plus radar signatures, known planned non-military launches, etc.).
In the case of earthquakes, their very unpredictability, the brief period of time avialable in which to make an alert (often only a few seconds, in cases a few minutes) means that manual cross-validation is all but impossible. Still, checks across multiple seismic detectors, preferably isolated from one another to the maximum extent possible, would be one potential check, though you'd still need to have multiple sensors relatively close together, as the time of propagation of seismic waves is both what provides the early alert and causes the damage. (Relative speeds of P (primary) and S (secondary) waves helps --- the p waves tend to cause less damage, but provide an earlier alert, the s waves arrive more slowly but do most of the damage.
At the surface, speed differential is about 3 km/s, meaning there's roughly 1 second of arrival differential for each 3km the observer is from the epicentre. (Subsurface waves travel faster.) Each 3km of separation of seismic stations costs 1 second of advanced warning time, plus whatever system logic and response times exist.
But given that major earthquakes can occur suddenly and without warning or pre-shocks, you really do pretty much have to be ready for anything at any time. And alerting systems need to take this into account. One option might be to have the logic on the phone itself --- it would trigger an alert, but only if some number of independent alarms were detected. One would be unlikely to trigger a false alarm, but two or three near-simultaneous alerts would indicate a major quake.
Penalising false alarms is probably the wrong approach. An engineering philosophy, of determining paths to either false positives or false negatives (each of which have high impact), and eliminating those.
> In the case of earthquakes, their very unpredictability, the brief period of time avialable in which to make an alert (often only a few seconds, in cases a few minutes) means that manual cross-validation is all but impossible.
For the earthquake alarm there is absolutely no manual intervention. These are automatic alarms exploiting the fact that the speed of light in air is faster than the speed of sound in rock. Earthquakes move approximately 1km/s, so if you are 3km away from the epicenter, you get a maximum of 3 seconds warning. Throw a human in the loop and there's no way they'd respond fast enough.
Often these false alarm incidents occur due to issues with the "last mile" of the system in the US, which might be substantially alleviated if there was a federal effort to get automation in place. In a nuclear strike, for example, NORAD would issue the alarm ("attack warning") via FEMA NAWAS and EAS after several documented and proceduralised validation steps.
The problem is that after FEMA NAWAS delivers the alert (audibly) to state and local EOCs, the next step is a ???. In those areas that do have some type of state or locally operated warning system, it's usually just some staff member pushing a button... and the button pushing is where mistakes can and do get made. In theory IPAWS and CAP will introduce automation at this step, but there's a lot of issues that have made CAP implementation slow, mainly the budgetary limitations of local governments and the fact that the major IPAWS/CAP software vendors expect very high prices.
Obviously in the case of earthquake warnings the options for manual validation are very limited due to the time constraints... but in general false-positive incidents have come from fat fingering, not misidentification by technical systems. There are good opportunities to put safeguards in place for automated systems to reduce false positives. For example (although I believe this is partly manual), as I understand it the Pacific Tsunami Warning Center will not issue a full warning until multiple data buoys have indicated a tsunami wave. That doesn't guarantee that it will be of damaging proportions once it reaches our coasts due to the vagaries of ocean modeling (i.e. in the case of the major Japanese earthquake in which a tsunami did occur but was quite small by the time it reached Hawaii, so the warnings felt a bit silly), but it does ensure that it's not an outright false positive.
My point is that more broadly false alarms a failures to alarm must be individually reviewed and cause for failure identified. Assuming that all more most failures are last-mile will work ... until it doesn't. Reviewing and demonstrating that the failure was or was not "last-mile" is what's required.
False signal, improper sensor detection, bad comms (generating or inhibiting signal), bad processing, confusing training or testing events for actual, having an actual alert during a test or drill, and errors in broadcasting alerts to the general public and/or the response to those alerts, might all be components to assess. "Last mile" concerns that last stage.
Since it's one that's often outside the core of an alerting system, and may involve many independent entities (people and/or organisations), it is likely to malfunction. Streamlining procedures and drilling frequently will help identify any such issues and iron them out.
Note that though tsunamis move quickly (> 800 kph / 500 mph in open ocean), the fact that they are often travelling immense distances (100s or 1,000s of miles or km) means that there are almost always many minutes, and quite often many hours for alerts to be sent and responded to. Earthquakes afford seconds to minutes, the timeframes are nearly two orders of magnitude less.
It's not clear who should be blamed for the Hawaii event, except for general government incompetence. It was a planned drill, but the exact time of the drill was purposefully not communicated to the team which handles the alert, to see how they respond. The manager of that team read out the alert text and concluded with: "This is not a drill. This is not a drill. This is not a drill."
The guy whose responsibility to push out the alert had to make a split-second decision. He knew there was a drill happening sometime that day, but his boss said (three times!) that this was not the drill. Better safe than sorry: he pushes the button. I can't really fault him.
Arguably the boss-man should face the repercussions for saying it wasn't a drill when it was, but then that's also kinda the point of the drill--to see how the team would handle a "live" situation. Maybe their interface should have been mocked or the actual alert disabled right before the drill, unbeknownst to them? So it is the drill planners that are responsible?
It's really hard to nail down an individual at fault here, rather than general bureaucratic incompetence.
I have a friend who was stationed in Hawaii during that alarm. He is fairly high up in naval ranking.
We met through an extreme sport hobby in which there are personal speed records to set, and setting those past a certain point are quite dangerous to ones body/life. He and I were both past said point back then.
He was living alone at the time and was woken up by the alert. Through his mind went “either this is a false alarm, or I am completely fucking dead and there’s nothing I can do about it”
Did absolutely nothing except put on his gear & went out and set a new speed record far into the “one fuckup and you’re severely injured or dead category”
I don't know, but my guess would be "free soloing". Basically, climbing up a rock face with no safety equipment. Enthusiasts keep track of speed records for popular climbs. Records are often proven with personal gopro footage, eye witness, etc.
I wonder what 'personal' means in his context though. A lot of the big speed runs, el cap, that face in squamish, are pretty established and not a super personal experience, like say picking your favorite one pitch and doing it.
But I am shocked at how many climbers I know who free solo more than 40 feet off the deck...
Close. Custom built electric skateboards. If I say much more I’ll doxx myself (pretty much already have on this account, oh well, drgaf)
At the time I believe he hit 47mph on flat land with completely smooth pavement. As a community we’ve now hit 54mph clocked on an actual speed radar uphill, slightly above 54mph uphill on GPS (but we don’t brag about GPS readings - while they’ve often been spot on, we’ll always say +/-2mph for them), 67 mph on flat land…
Uphill was on custom poured rubber tires. 67mph flat land was on store available urethane wheels. Keep in mind that’s all electric with no energy from an initial downhill start.
We’ve skated with three of the four downhill record holders of 90mph+… they’re fucking insane in general, & the first time we put one on a custom eboard he hit 44mph flat land & stable with ease (steez)
On the note of danger… we’ve had somebody die from a 14mph flat land crash… yet my friend completely walked away from a 47mph crash wearing only a helmet and tumbling 360* four times… crashes over 40-45 mph in general get pretty fucking gnarly, I’ve seen a few people become seriously disabled or have to completely leave the sport from one, & all of the top dudes of the community wear full leather & more now that they’re pushing past 50mph.
It’s definitely fun stuff. There are some speeds you just shouldn’t be going on a plank of wood. As for me, I’ve clocked 48mph flat land on gps, 45 on radar speed trap. I got into the low 40’s roughly three months in to the hobby, but going past that is not particularly something I’m focused on at this point in my life. Over 45 mph on anything but perfectly smooth road (aka not often) gets to be genuinely scary & induces hardcore tunnel vision. Uphill & flat land is so much different than downhill. A speed wobble @ 38mph steep uphill may have genuinely been the scariest experience in my life, & I’ve had a gun in my face.
If I had to warrant a guess I'm gonna say it's wingsuit flying. I can imagine his friend living at the top of a mountain putting on his squirrel suit to get one last glimpse of Hawaii before shit hits the fan.
The problem is that if the frequency of false alarm is high enough, people ignore the real ones. There is also a problem where the alarm causes harm or causes people to unintentionally become harmed.
In Poland, it was common to use alarm sirens on the occasion of national holidays, even the less important ones. I was so used to meaningless alarm signals that hearing one was making me wonder what anniversary it was, instead of thinking about the potential dangers.
I'm not sure if it was a nationwide problem – voivodes (provincial govenors) could arbitrarily decide on the use of such a signal to commemorate important events. Maybe it changed since then.
I have extended family members who are employees of Hawaii's State Government. The stories they tell... Let me just say that the sheer incompetence and horrible systems design people claim are responsible for that day are entirely reasonable.
The heart of the problem is that government jobs are extremely lucrative for the people of Hawaii because they pay well and because it is extraordinarily difficult to get fired from one. While direct nepotism isn't common, everyone is basically part of this giant extended family. Knowing the right person can land you one of these jobs-for-life even if you're barely qualified for it. There is also a culture of not rocking the boat. Trying to get freeloaders fired subjects you to ostracism. So what ends up happening is a few people end up doing the majority of the work. While this isn't unique to Hawaii, those people who are actually productive end up following their own version of 'the process' and the result is that people are rarely sure if what they are told to do is really what they should be doing.
I would like to submit this as supporting evidence: "A password for the Hawaii emergency agency was hiding in a public photo, written on a post-it note"
I seen too many times when something is made by someone who understands what the system does but never thinks what a rank beginner who is suddenly facing the same display going to think.
It is hard to remember what it is like for someone new to a system.
I got goosebumps reading your post and seeing the screenshot. I used to live in a seismic active region and experienced a few 6.0 and understand that a 9.0 is an end of the world event.
Most you weren't alive then but Alaska had a 9.2 earthquake in 1964. I well remember the news accounts. Luckily not that many people lived in Alaska at the time. I cannot imagine if a quake of that magnitude hit modern day San Francisco.
"9.0 and greater. At or near total destruction – severe damage or collapse to all buildings. Heavy damage and shaking extends to distant locations. Permanent changes in ground topography. One per 10 to 50 years."
I've got no idea at what magnitude I should start worrying. I would assume, and hope, that if my phone (which is otherwise on silent) is blaring, it must be a big deal. Maybe for some people a 4.3 is a big deal, but not for all...
I think that although (estimated) magnitude is helpful, Japan's system also calculates the (estimated) intensity from the earthquake for your local area. Not always correct (but this tends to be rare), but usually within +/-1 of the Shindo scale (which is their local intensity scaling). Seems that ShakeAlert doesn't compute (yet, hopefully) the estimated intensity in your area.
This isn't my experience at all and I've lived in the Bay Area nearly half my life. I have a vague idea of what a mag 4 earthquake feels like, and that's about it.
Yeah that makes sense, people talk about what magnitude x "feels" like, but they're really describing an earthquakes intensity rather than magnitude. You don't directly "feel" the magnitude.
Any given magnitude quake is going to feel very different for people in different situations - eg how far away, how deep, soil conditions, how tall the building they are in etc...
Magnitude is related to how much energy is released - useful for seismologists and records, while intensity is related to ground acceleration and subjective effects which is useful for structural engineers and the public caught in one.
eg that 6.2 magnitude Christchurch quake mentioned elsewhere still managed to produce some of the highest ever recorded vertical ground accelerations despite releasing a tiny fraction of what a really big quake can do.
This depends greatly on building codes, structure contents, and local geology.
In California and Japan, decades of stringent building codes mean that most structures are likely to be safe agaist even large quakes, in the sense that occupants should survive, even if the structure itself is not repairable.
Along the central and eastern US, and in large parts of rural China, Iran, Iraq, and Turkey, amongst other areas, building codes, geology, and general preparadness and awareness (or lack) can make even comparatively small quakes deadly.
From the Rockies east, the US is underlayed by largely-intact limestone and a thick crust which can propagate seere ground movement hundreds of kilometers, up to 1,000 km or more. By comparison, along th USwest coast, being 100--200 km from an epicentre usually renders even a large quake largely harmless (though it may still be felt). Additionally, construction standards in the central/eastern US and other regions mentioned above tend to result in far more severe structural damage. Rescue, aid, and shelter capabilities may also be limited.
(In California, the principle geological hazard is fill or other soils prone to liquefaction, which can greatly amplify movement locally. Landslides may also be a concern. In mountains, rockslides.)
The guidelines 323 gives are useful for California and Japan. Elsewhere, comparable damage might occur a magnitude below those given.
Here in Ontario we had a small quake caused by a rock slide in Lake Ontario, almost no damage was seen. But my friend in Bowmanville said her grand mother lost tens of thousands of dollars in custom plates that she has displayed on ledges all around her house.
Why? Because we never get earthquakes here, so there were no lifted edges or holders! Then suddenly we get a small quake, and they all came crashing down.
Christchurch, New Zealand was smashed by a 6.2. Pretty much as you say, older and poorly designed building didn’t fare well, and the earlier 7.2 earthquake wouldn’t have helped. It was a very shallow earthquake too.
The strike slip fault system in most of California can produce earthquakes up to about 8.0. Subduction zone earthquakes that occur in many places, like Northern California up to Alaska, Chile, Japan, etc, can produce 9+ earthquakes. 10 and above only occur during large impact events. So California can have buildings "earthquake proofed" for much lower cost than say Seattle and they come at higher frequency. That may be one of the reasons that California's infrastructure is pretty well prepared for coming earthquakes while Seattle will have major damage when the next 9.0 hits in 0-400 years.
The most dangerous fault line in Seattle, both in terms of earthquake and tsunami risk, is the eponymous system of shallow thrust faults[0] that run through the middle of the city and historically have produced ~7.0 earthquakes.
Seattle buildings built in the last 3 decades are explicitly designed to survive extreme earthquakes. Most of the risk is in the 1970s and earlier infrastructure, quite a lot of which has been torn down to make room for the massive growth of Seattle.
There’s also a healthy local trade in earthquake retrofitting. After the nisqually quake the city got pretty serious, a lot of old buildings downtown were severely damaged
The modern building codes are derived from a 9.0 subduction zone model. I've heard people say that building standards derived from this model should work for just about any type of earthquake up to around 8.0-8.5 even if not specifically modeled; I have no idea how true that is but it seems plausible. Building codes are not defined just by the strength of the earthquake but also the earthquake type, depth, soil etc. It isn't the strength that is the problem so much as the kinds of loads different earthquakes put on structures.
Seattle has a couple ~7.0 earthquakes every century, so the city has experience with strong earthquakes and everything old that is still standing has at least some ability to resist earthquakes (survivor bias). The last big earthquake was in 2001 (magnitude 6.8).
a number of years ago, i worked in one of the downtown LA office towers when a 5.x earthquake hit. it was a jolt and rumble, and looking out the window, we saw the other towers nearby swaying back and forth. then we realized we were also swaying back and forth. it was unnerving to say the least. the little engineer in me eventually kicked in to point out that that engineered-in flexibility was what kept us from breaking apart and crashing into the ground.
We had had an earthquake in low 5's here a couple years earlier. That was nerve-wracking but didn't do any damage. So I think I was gauging my reaction (mostly instinctively) off that.
Actually, I just looked up the previous earthquake:
Distance from the epicenter matters as well. I was 6 miles from a 4.9 last month, my first real earthquake. It was unsettling and concerning (including for the people I was on zoom with) but that was it. Nothing fell off the walls, iirc no fatalities or buildings demolished.
The scale is logarithmic. My rule of thumb is that 5 is where things start to get much more dangerous.
It depends how close you are to the epicenter, of course. Your figure seems about right to me: I think a 5.0 near an epicenter would be pretty violent. But I've never been near an epicenter — only on the outskirts.
It also depends on what type of ground you're on. I've been in 5+ earthquakes in a house built on solid rock (Los Angeles area hills), and a 4.5 down in the valley. Being on loose ground makes it feel much worse.
You get a feel for that with the shaking frequency and/or gap between different sets of waves (P & S waves). No discernable gap and higher jerkier frequency usually means closer, a longer rolling feeling with separated phases that might last longer usually means further away.
Just like sound or ocean waves the higher frequencies attenuate out quicker over distance.
Even if you had been given 60 seconds warning, what kind of mitigation can you do for a magnitude 2,4,6? Is there anything to be done if you are walking on the street/in a car/in a N floor building?
I do not live in an earthquake prone region, so trying to understand the rationale. With tornadoes, theoretically you could move to a structurally sound room, but I am unsure if there is any such thing to be done for an earthquake.
I understand you can hide under a table (won’t help if the building collapses but you won’t be whacked in the face by a bottle or bookshelf flying through the room), stand in the doorframe (these offer some protection AFAIU if the building gets damaged, or even run out into the open space.
It depends on where you live and the kind of earthquakes that occur there.
I spent a couple of years in Chile, where deep earthquakes are common. Anything below magnitude 5 was often not even noticeable. Magnitude 5 earthquakes happened a few times a year in the area, and they were business as usual. The ground shook a little, there was some noise, and tall buildings were swaying afterwards. I experienced one magnitude 6 earthquake, which was a bit scary, but it didn't do any noticeable damage and the locals didn't seem to care.
Now I live in California, where earthquakes are rarer and more shallow. Magnitude 4 is already noticeable, and I guess magnitude 5 could do some local damage.
The biggest immediate danger is usually getting hit by flying/falling debris. Outdoors, you should get away from trees, power lines, traffic signs, buildings, etc. Indoors, you should avoid windows and tall furniture such as bookshelves, and maybe take shelter under a sturdy table or in a doorway.
> what kind of mitigation can you do for a magnitude 2,4,6?
Simply walk outside? If you have an empty area nearby that's an extremely safe spot to be in an earthquake.
If you're in a car, get out from an underpass? A lot of deaths were due to a freeway overpass pancaking in SF.
Open your garage door? This is one of the big things that is supposed to happen in California. Fire departments are supposed to have an automated system that pops the garage doors when there is an earthquake so the trucks don't get trapped by bent doors.
This made me think one should almost practice like a fire alarm drill we do in grade schools. Set a random timer and when you get the alert react. Have it go off randomly some days so you can practice getting under a desk or in a doorway as fast as possible.
Having attended grade school in BC, Canada, we used to do exactly that. Someone would come on the PA system to rattle some rocks in a jar and all students would duck under the desks until the 'earthquake' subsided, then count to 60 and quietly file out to the field.
In the years after the disaster of 1999 [1], we used to do exactly that in Turkey in the 2000s, couple times a year. I'm not sure when/why they stopped.
On a not-too-closely-related note, the last time I heard of one was in 2013, when a group of riot police forcibly dispersed a civilian drill. This was a few months after the Gezi Park protests.
I got my first tornado alert in last week's outburst of tornadoes in the midwest.I wasn't worried about it until the tornado sirens started going off. I became quite concerned when I saw the clouds. I'd never seen them so low and moving so fast. 24 confirmed tornadoes!
Luckily, they were no where near as powerful as the ones that KY got earlier this month, but it was still alarming.
And then the geniuses decided to do a test of the system yesterday at 11PM.
In case this helps, I recommend registering with nixle [0] for any emergency notifications to your phone. It provides more accurate and real time details from local agencies in your area.
It was an interesting fleeting experience. I was sitting on the couch, phone in hand, when it emitted an unusual fairly obnoxious noise. I glanced at the screen, saw the words earthquake and 4 something, and understood what was being conveyed sort of inchoately without making it explicit sense of it. My wife was sitting next to me reading so I turned to her and tried to show it to her but she remained absorbed in her reading.
Then the room jolted, rocked a little, and settled. The nice thing about the alert is I remained relaxed the whole time. Because the alert indicated the magnitude, I wasn't too worried about damage or personal injury.
Now if it had warned of a larger earthquake, like a 5 or 6, I imagine I would have been more panicked. Still, the warning would have been even more valuable in that case.
It was one of the more acute "Now this feels like living in the future" moments I've had recently.