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Of course I was offline during SoCal’s M6.4 earthquake.
Please fill out your Did You Feel It? reports here: earthquake.usgs.gov/earthquakes/ev…
Please fill out your Did You Feel It? reports here: earthquake.usgs.gov/earthquakes/ev…
Location, location, location: This was a significant earthquake, shallow so the shaking was felt most intensely over a small area, but out in the Mojave desert where the population density is low.
📷 AP, who are full of crap calling this part of the Ring of Fire.
📷 AP, who are full of crap calling this part of the Ring of Fire.
Q: Hey, that looks REALLY far inland to be part of San Andres Fault...
A: Yeah, it’s way off the main large fault system, in the extended fault zone composed of a whole bunch of modtky-parallel-ish smaller faults.
📷 USGS (& a midifued USGS, ignore the study area arrows)
A: Yeah, it’s way off the main large fault system, in the extended fault zone composed of a whole bunch of modtky-parallel-ish smaller faults.
📷 USGS (& a midifued USGS, ignore the study area arrows)
Q: Ahhhh! Ahhhhhhhh! AHHHHH!
A: Wait, what?! No! Calm! It’s okay!
Today’s going to be a day of aftershocks, a lot of them felt by the massive population of LA and the coast up by Santa Barbara.
No panicking. Drop, Cover, Hold On. Can’t drop? Lock.
You got this. Breathe.
A: Wait, what?! No! Calm! It’s okay!
Today’s going to be a day of aftershocks, a lot of them felt by the massive population of LA and the coast up by Santa Barbara.
No panicking. Drop, Cover, Hold On. Can’t drop? Lock.
You got this. Breathe.
Q: What causes aftershocks?
A: An quake happens with stress gets too high & a fault breaks. But only part of it moves.
Stress goes down where it moved (ruptured), but up where it didn’t (locked). That stress can trigger new quakes.
📷 Stein (USGS)/Toda (Kyoto University)
A: An quake happens with stress gets too high & a fault breaks. But only part of it moves.
Stress goes down where it moved (ruptured), but up where it didn’t (locked). That stress can trigger new quakes.
📷 Stein (USGS)/Toda (Kyoto University)
Earthquakes are all about redistributing stress.
Think of it like a puppy pile. As one pup moves, the others squirm around to get comfy. The bigger the puppy (higher magnitude quake), the more movement to reshuffle (more aftershocks).
The aftershocks drop off exponentially.
Think of it like a puppy pile. As one pup moves, the others squirm around to get comfy. The bigger the puppy (higher magnitude quake), the more movement to reshuffle (more aftershocks).
The aftershocks drop off exponentially.
Q: Did BC cause this with its M6 last night? *suspicious glare*
A: I like your logic, but no. The Earth is REALLY big.
BC & SoCal are way too far apart for their faults to transmit stress to each other.
A: I like your logic, but no. The Earth is REALLY big.
BC & SoCal are way too far apart for their faults to transmit stress to each other.
Tectonic plates are constantly crawling at roughly the same rate your fingernails grow. (Manicures are reminders to check your quake kits & plans!)
Earthquakes are normal. We get 100-200 M6 quakes a year, an average of a few each week.
Stats: gizmodo.com/a-quick-guide-…
Earthquakes are normal. We get 100-200 M6 quakes a year, an average of a few each week.
Stats: gizmodo.com/a-quick-guide-…
BC and CA have fundamentally different types of earthquakes. (& San Andres the movie stole Cascadia’s style. It’s ok, love it anyway.)
Plates can pull apart, push together (BC), or slide side-by-side (CA). Transform zones like California have more frequent shallow M6-M7
📷 USGS
Plates can pull apart, push together (BC), or slide side-by-side (CA). Transform zones like California have more frequent shallow M6-M7
📷 USGS
Incidentally, this is why California’s not part of the Ring of Fire.
The Ring is subduction zones, places where ocean plate dives deep, melting to produce explosive volcanoes & capable of rare M8-9 quakes
It’s a geologically meaningless term, but it’s not California.
The Ring is subduction zones, places where ocean plate dives deep, melting to produce explosive volcanoes & capable of rare M8-9 quakes
It’s a geologically meaningless term, but it’s not California.
Aside:
Hawaii: Also not part of the Ring of Fire as it’s an oceanic hotspot with effusive volcanoes.
Literally every Ring of Fire map (including the one I used) is misleading. It’s a common teaching mnemonic, but is such a huge source of misconceptions. Just forget it.
Hawaii: Also not part of the Ring of Fire as it’s an oceanic hotspot with effusive volcanoes.
Literally every Ring of Fire map (including the one I used) is misleading. It’s a common teaching mnemonic, but is such a huge source of misconceptions. Just forget it.
Q: Why didn’t the ShakeAlert early warning system trigger when so many people felt it?
A: An M6 200km from LA is far enough away to have the felt intensity of a nbd quake despite still having the duration of a significant quake
My guess? Didn’t qualify as worth triggering.
A: An M6 200km from LA is far enough away to have the felt intensity of a nbd quake despite still having the duration of a significant quake
My guess? Didn’t qualify as worth triggering.
Disaster warnings are a tricky balance.
California gets a lot of earthquakes, and they’re shallow so the felt intensity is focused to smaller areas (vs deep quakes that shake bigger areas less intensely)
If you send too many alerts, people zone out & ignore them. Prioritize.
California gets a lot of earthquakes, and they’re shallow so the felt intensity is focused to smaller areas (vs deep quakes that shake bigger areas less intensely)
If you send too many alerts, people zone out & ignore them. Prioritize.
Pretty much everyone in California has been startled by an M3-4, then shrugged it off. Culturally, M5s are where people start caring.
But we don’t have much practice with slightly-distant large earthquakes. “It feels like an M4 but goes on forevvver like an M6” is a grey zone.
But we don’t have much practice with slightly-distant large earthquakes. “It feels like an M4 but goes on forevvver like an M6” is a grey zone.
Ahhh, here we go!
That’s not a science or engineering failure, but an expectations mismatch.
It’s going to be a learning curve to figure out what types of warnings people want without oversaturating & desensitizing.
(tip via @scadaman)
That’s not a science or engineering failure, but an expectations mismatch.
It’s going to be a learning curve to figure out what types of warnings people want without oversaturating & desensitizing.
(tip via @scadaman)
Q: Intensity vs magnitude pls?
A:
Magnitude is a quantitative measure of energy released. It’s a single number (although it may get revised as we update data & math).
Intensity is a qualitative measure of how the shaking felt. It’ll change with distance, geology, buildings.
A:
Magnitude is a quantitative measure of energy released. It’s a single number (although it may get revised as we update data & math).
Intensity is a qualitative measure of how the shaking felt. It’ll change with distance, geology, buildings.
The more of a fault that moves, the more energy is released.
The tricky bits are calculating (normal for estimates to fluctuate for a while) & that pop culture will NOT let Richter scale just die already. It’s moment magnitude for 30+ years.
Details: earthquake.usgs.gov/learn/topics/m…
The tricky bits are calculating (normal for estimates to fluctuate for a while) & that pop culture will NOT let Richter scale just die already. It’s moment magnitude for 30+ years.
Details: earthquake.usgs.gov/learn/topics/m…
But felt intensity is fascinatingly complex.
By default:
closer = more shaking
(thus: shallower = more shaking)
softer geo (sediment) = more shaking
taller buildings = more shaking
wetter = more shaking
These can combo funky so a far river valley feels more than a near mountain
By default:
closer = more shaking
(thus: shallower = more shaking)
softer geo (sediment) = more shaking
taller buildings = more shaking
wetter = more shaking
These can combo funky so a far river valley feels more than a near mountain
Aside:
Mexico City is in a basin of hard rock (bouncing seismic waves into the city) on top of saturated sediments (which amplify shaking).
We legit got confused for years thinking it was the epicentre of several distant earthquakes because the felt intensity was higher.
Mexico City is in a basin of hard rock (bouncing seismic waves into the city) on top of saturated sediments (which amplify shaking).
We legit got confused for years thinking it was the epicentre of several distant earthquakes because the felt intensity was higher.
Swimming pool seiche! Yesssss
Seiche are resonance waves in included water bodies. Think scooting back & forth in a tub so waves keep getting bigger.
Swimming pools resonate at the smaller quake frequencies (~5s) even hundreds of miles away.
Seiche are resonance waves in included water bodies. Think scooting back & forth in a tub so waves keep getting bigger.
Swimming pools resonate at the smaller quake frequencies (~5s) even hundreds of miles away.
With a tiny bit of luck, the earthquake set off a seiche in Devil’s Hole, Nevada and endangered desert pupfish will get their groove on in the near future.
Details [my old 2018 story]: smithsonianmag.com/smart-news/end…
Details [my old 2018 story]: smithsonianmag.com/smart-news/end…
Thread splinter:
I’m doing a fun-but-unnecessary puppies-as-earthquakes extension over here just because I can.
Want moar puppies? Go ask questions.
I’m doing a fun-but-unnecessary puppies-as-earthquakes extension over here just because I can.
Want moar puppies? Go ask questions.
Q: It sounds like seismology involves a lot of math & a lot of unknowns...
A: Yup. Real life rocks are complicated & confusing.
That’s part of why we don’t (yet) know exactly which fault was moving today.
A: Yup. Real life rocks are complicated & confusing.
That’s part of why we don’t (yet) know exactly which fault was moving today.
Earthquake x space
(I have interviews on Deep Space Network disaster preparedness that I really want to write some say. It’s intense.)
(I have interviews on Deep Space Network disaster preparedness that I really want to write some say. It’s intense.)
Despite how complicated intensity can be, we’ve got a pretty good handle on theory.
Nice mini-thread that gets at the (very few) discrepancies between anticipated vs reported shaking:
Nice mini-thread that gets at the (very few) discrepancies between anticipated vs reported shaking:
For the geotechnically-included: a preliminary stress assessment of how 1872 & 1992 quakes may have set up today’s quake (& what the new stress transfer may look like)
temblor.net/earthquake-ins…
tip via @alexwitze
temblor.net/earthquake-ins…
tip via @alexwitze
This is a nice demo of earthquake frequency. How long does it take the crystals to swing back & forth?
jingle jingle jingle
jingle jingle jingle
The most significant damage from today's earthquake was already repaired.
As a geophysicist, I'm hoping they don't repaint the road lines. Just let them stay offset marking how much this fault moved.
As a geophysicist, I'm hoping they don't repaint the road lines. Just let them stay offset marking how much this fault moved.
Q: Hey, why were you talking about road lines?
A: Californian faults move sideways past each other. You can see how much the ground moved! (with a fresh line from last night indicating it didn't keep creeping)
A: Californian faults move sideways past each other. You can see how much the ground moved! (with a fresh line from last night indicating it didn't keep creeping)
Q: AHHHH WHAT THE FUCK, WHY WAS THERE A BIGGER EARTHQUAKE?
A: You're okay. You remembered to drop, cover, hold on, right? Good! Fill out your Did You Feel It? report here, then come back and we'll chat.
earthquake.usgs.gov/earthquakes/ev…
A: You're okay. You remembered to drop, cover, hold on, right? Good! Fill out your Did You Feel It? report here, then come back and we'll chat.
earthquake.usgs.gov/earthquakes/ev…
The magnitude of the latest earthquake is still a bit TBD (that's normal, we need humans to go in and check the computers), but is probably M6.8-7.1ish. Bigger than the July 4th quake.
To get back to our puppy pile, someone just kicked a nose.
To get back to our puppy pile, someone just kicked a nose.
This isn't exactly normal -- aftershocks are smaller than the main quake -- but it's also not entirely unexpected.
From the July 4 aftershock forecast (earthquake.usgs.gov/earthquakes/ev…)
getting an M7 this week had a ~0.5% chance of happening. Rare, but not ridiculously so.
From the July 4 aftershock forecast (earthquake.usgs.gov/earthquakes/ev…)
getting an M7 this week had a ~0.5% chance of happening. Rare, but not ridiculously so.
Technically, now the July 4 earthquake & everything since then were foreshocks, this one is the main quake, and everything next are aftershocks.
...yeah. I know. We have to name them retroactively. Nature doesn't give us ID labels. Sorry?
...yeah. I know. We have to name them retroactively. Nature doesn't give us ID labels. Sorry?
BUT! One of the badass things about this is that you JUST practiced how to do earthquakes! You just got your reminders! You totally spent the today securing bookcases to walls, strapping down TVs, and all that jazz, yeah?
Even if you did no new prep, you probably panicked less.
Even if you did no new prep, you probably panicked less.
Q: Does this mean we're working off stress so we won't have The Big One?
A: Ridgecrest just DID have The Big One. Give 'em a hug.
But no. Magnitude is logarithmic. It takes 100 M6 quakes to release the energy of an M7 quake, 1,000 to release the energy of an M8, 10,00 for an M9
A: Ridgecrest just DID have The Big One. Give 'em a hug.
But no. Magnitude is logarithmic. It takes 100 M6 quakes to release the energy of an M7 quake, 1,000 to release the energy of an M8, 10,00 for an M9
Q: That felt REALLY weird... (see QT)
A: You might be feeling the different seismic waves. Love waves arrive first, then Rayleigh waves. Love shakes you side-to-side. Rayleigh feels like rolling ocean waves (it makes me kinda seasick).
A: You might be feeling the different seismic waves. Love waves arrive first, then Rayleigh waves. Love shakes you side-to-side. Rayleigh feels like rolling ocean waves (it makes me kinda seasick).
Q: I AM NEVER GOING TO SLEEP AGAIN.
A: Everyone go grab sturdy shoes & a flashlight. Those live by (or under) your bed now. If a disaster hits at night, you might be evacuating with no power & lots of debris. (This goes for hurricane/tornado peeps, too)
A: Everyone go grab sturdy shoes & a flashlight. Those live by (or under) your bed now. If a disaster hits at night, you might be evacuating with no power & lots of debris. (This goes for hurricane/tornado peeps, too)
Q: I AM STILL NOT SLEEPING.
A: Bed by a window? Close the blinds to protect from breaking glass. Any mirrors, pictures, bookcases, or other hazards? Make sure they're secure (or take 'em down).
Quake while you're in bed? Curl up & use pillow to protect your neck & head.
A: Bed by a window? Close the blinds to protect from breaking glass. Any mirrors, pictures, bookcases, or other hazards? Make sure they're secure (or take 'em down).
Quake while you're in bed? Curl up & use pillow to protect your neck & head.
Q: I AM SLEEPING UNDER A TABLE.
A: You know what? That's cool. Probably overkill, but it's not going to hurt you.
In North America, you're more worried about crap inside the building falling on you than you are about the building collapsing. A sturdy table is a good bedmate.
A: You know what? That's cool. Probably overkill, but it's not going to hurt you.
In North America, you're more worried about crap inside the building falling on you than you are about the building collapsing. A sturdy table is a good bedmate.
Q: Okay, so... what if THIS is a foreshock?
A: I'm so sorry, but it might be. The odds are small (& I'm waiting for USGS to calculate because that's beyond my lane), but it's possible a bigger quake is coming.
We cannot predict exactly when, where, or how big the next quake is.
A: I'm so sorry, but it might be. The odds are small (& I'm waiting for USGS to calculate because that's beyond my lane), but it's possible a bigger quake is coming.
We cannot predict exactly when, where, or how big the next quake is.
Each fault system is building up stress, and the bigger faults have multiple segments.
Having a M7 in the Mojave faults aren't going to release all the stress built up on the San Andreas (nor that kink north of LA). That stress is still locked.
Having a M7 in the Mojave faults aren't going to release all the stress built up on the San Andreas (nor that kink north of LA). That stress is still locked.
It is HIGHLY UNLIKELY for California to start having M8 or M9 earthquakes.
California has transverse faults: tectonic plates slide sideways. The "Big One" quakes are ~M7ish.
We see M8+ in subduction zones (Pacific Northwest, Chile, Alaska, Japan...)
California has transverse faults: tectonic plates slide sideways. The "Big One" quakes are ~M7ish.
We see M8+ in subduction zones (Pacific Northwest, Chile, Alaska, Japan...)
Q: I am freaking the fuck out. What can I do to productively channel that anxiety into useful preparedness?
A: This is going to be a long list! Don't try to do everything at once, but check off what you can while you can.
A: This is going to be a long list! Don't try to do everything at once, but check off what you can while you can.
1. Drill Drop! Cover! Hold on!
(Don’t have mobility to drop? Lock!)
Build muscle memory to drop down under sturdy furniture, protect your neck & head, and hold on to keep your furniture from waddling off without you.
(Don’t have mobility to drop? Lock!)
Build muscle memory to drop down under sturdy furniture, protect your neck & head, and hold on to keep your furniture from waddling off without you.
3. Prep for your pet.
Find their carry case. Write your contact info on it. Pack an overnight bag for them. Food, a water dish & water bottle, leash, toy, whatever they need to get through 1-3 days
Then take a selfie with your pet. It's proof of ownership if you're separated.
Find their carry case. Write your contact info on it. Pack an overnight bag for them. Food, a water dish & water bottle, leash, toy, whatever they need to get through 1-3 days
Then take a selfie with your pet. It's proof of ownership if you're separated.
4. Go on a home hazards hunt.
You're more likely to be hurt by things inside your home than by your building collapsing. What do you need to secure?
Game version: shakeout.org/beatthequake.h…
FEMA's list: fema.gov/media-library/…
Vancouver's list: vancouver.ca/home-property-…
You're more likely to be hurt by things inside your home than by your building collapsing. What do you need to secure?
Game version: shakeout.org/beatthequake.h…
FEMA's list: fema.gov/media-library/…
Vancouver's list: vancouver.ca/home-property-…
5. Say hi to your neighbours.
During an emergency, the very first people to respond are the people closest to you. If a building collapses or a fire starts, your neighbours will be the first responders on scene.
You're all awake anyway. Say hi. Build community resilience.
During an emergency, the very first people to respond are the people closest to you. If a building collapses or a fire starts, your neighbours will be the first responders on scene.
You're all awake anyway. Say hi. Build community resilience.
6. Pick an out-of-area contact.
If a major disaster happens, local communications are going to get flooded. Pick someone who lives Anywhere Else & make them your point of contact. Then you just make one call to check in that you're okay & learn who of your nearby kin checked in.
If a major disaster happens, local communications are going to get flooded. Pick someone who lives Anywhere Else & make them your point of contact. Then you just make one call to check in that you're okay & learn who of your nearby kin checked in.
7. Make a plan.
You've been meaning to forever. Do it while you can't sleep.
This is BC-specific, but you can scribble out the Canadian bits and write in US info: www2.gov.bc.ca/gov/content/sa…
I like it because they're fill-in-the-blank guides for a whole range of living situations.
You've been meaning to forever. Do it while you can't sleep.
This is BC-specific, but you can scribble out the Canadian bits and write in US info: www2.gov.bc.ca/gov/content/sa…
I like it because they're fill-in-the-blank guides for a whole range of living situations.
8. Pack a kit. Actually, pack 2 kits.
Grab & Go: What do you need to grab, bail out NOW, and be okay until morning?
Stay & Survive: What do you need to shelter at home for at least 3 days, maybe a week?
Make sure to include comfort items. (Good book, cards, chocolate.)
Grab & Go: What do you need to grab, bail out NOW, and be okay until morning?
Stay & Survive: What do you need to shelter at home for at least 3 days, maybe a week?
Make sure to include comfort items. (Good book, cards, chocolate.)
9. Breathe.
Seriously, take a moment to relax. Breathe deep. Find some calm.
A shocking number of people die or are injured from panic during earthquakes, either from heart attacks or by doing things like leaping out windows.
Seriously, take a moment to relax. Breathe deep. Find some calm.
A shocking number of people die or are injured from panic during earthquakes, either from heart attacks or by doing things like leaping out windows.
10. Go for a walk & play "What would I do if there was an earthquake?"
Identify places you really don't want to be (lots of overhead wires, huge balconies, under skyrises with lots of windows, in buildings with soft stories like garages/display windows) & where you'd shelter.
Identify places you really don't want to be (lots of overhead wires, huge balconies, under skyrises with lots of windows, in buildings with soft stories like garages/display windows) & where you'd shelter.
Q: Why did Dr. Jones say this was 5% odds & you said 0.5%?
A: 5% odds any earthquake larger than the first would happen. 0.5% that the larger would be M7+ (which this may or may not have been, still TBD).
Different scenarios, same concept.
A: 5% odds any earthquake larger than the first would happen. 0.5% that the larger would be M7+ (which this may or may not have been, still TBD).
Different scenarios, same concept.
Secure bookcases & other large furniture. (Renting? You'll patch on move-out.) Even an Ikea table will protect you from a hanging lamp or books.
Nearly empty home? Great! That means nothing can fall on you. Curl up & protect your head & neck.
Nearly empty home? Great! That means nothing can fall on you. Curl up & protect your head & neck.
With earthquakes it's all about location.
If an M6 or M7 is directly under a city, it can cause massive damage. But in the desert where population density is lower? It'll be less damage because there's less TO damage
(Again, give Ridgecrest friends hugs)
If an M6 or M7 is directly under a city, it can cause massive damage. But in the desert where population density is lower? It'll be less damage because there's less TO damage
(Again, give Ridgecrest friends hugs)
If M6 or M7 are the city-destroying earthquakes, M8 or M9s are region-destroying. If one happens in the Pacific Northwest, it's going to impact a whole lot of people no matter where it is.
But M8 & M9 happen in subduction zones, not SoCal. (Far NorCal, you're with PNW.)
But M8 & M9 happen in subduction zones, not SoCal. (Far NorCal, you're with PNW.)
Q: Are these SoCal earthquakes going to trigger an earthquake in San Francisco? In Portland? In Vancouver?
A: No.
The Earth is really big. The distances are far. The fault systems are separate. More details upthread & in puppy-thread.
See also:
A: No.
The Earth is really big. The distances are far. The fault systems are separate. More details upthread & in puppy-thread.
See also:
Daaammmn, that's a much bigger swimming pool seiche this time.
Assuming the initial M7.1 is still valid, tonight's earthquake released more than 10 times the energy as yesterday's M6.4. Calculate it here: earthquake.usgs.gov/learn/topics/c…
Assuming the initial M7.1 is still valid, tonight's earthquake released more than 10 times the energy as yesterday's M6.4. Calculate it here: earthquake.usgs.gov/learn/topics/c…
Okay, now this is fun. I'm going to make you play geophysicist.
Scroll up thread to the field photos of the crack in the road with the nicely-offset road line. From standing on one side, is the other side moving left or right?
Scroll up thread to the field photos of the crack in the road with the nicely-offset road line. From standing on one side, is the other side moving left or right?
Yup, North American is on the creatively-named North American Plate. We're all in this together.
Yes, that's exactly what aftershocks are!
The trick is now close is "close"? Check out the puppy thread (particularly howling) for more on that idea, but the energy released by the M7.1 earthquake absolutely impacted the stress on nearby faults.
The trick is now close is "close"? Check out the puppy thread (particularly howling) for more on that idea, but the energy released by the M7.1 earthquake absolutely impacted the stress on nearby faults.
From the USGS Latest Earthquake map (earthquake.usgs.gov/earthquakes/ma…), we've got another cluster happening a smidge farther north. Yes, those are all close enough that it's probably related faults all creaking & resettling
More technical:
More technical:
Far NorCal, up at Humboldt (& the southernmost Cascade volcano, Lassen), is actually on the Cascadia subduction zone with the rest of the Pacific Northwest (Portland, Seattle, Vancouver).
📷 USGS
📷 USGS
Q: Can we get a bonus prep tip?
A: Sure, you can always do more! Charge up external batteries, pack a charge cable in you go bag, and think about if you can pull off alternate forms of communication.
Such as:
A: Sure, you can always do more! Charge up external batteries, pack a charge cable in you go bag, and think about if you can pull off alternate forms of communication.
Such as:
Part of why tonight's earthquake felt different than usual MAY be because Californians are used to San Andreas and this cluster is in the Eastern California Shear Zone / Mojave Block.
Did it feel kinda like 1992 Landers?
Did it feel kinda like 1992 Landers?
Q: I live in the PNW and I kinda hate you right now.
A: I live in Vancouver, BC. I feel you so hard. I'll be on @GlobalBC tomorrow morning (~7:40?) to talk our quakes.
But it's not impossible to survive. Advice from Chile, home of M8 & M9 quakes:
A: I live in Vancouver, BC. I feel you so hard. I'll be on @GlobalBC tomorrow morning (~7:40?) to talk our quakes.
But it's not impossible to survive. Advice from Chile, home of M8 & M9 quakes:
Ack! Broken thread needs a quick patch:
Q: How severe are these aftershocks going to be?
A: @USGS website is still being funky, but their aftershock forecast is posted on FB: facebook.com/USGeologicalSu…
That's a near-certainty SoCal will get M6 aftershocks, 9% chance you'll experience an earthquake larger than the M7.1
A: @USGS website is still being funky, but their aftershock forecast is posted on FB: facebook.com/USGeologicalSu…
That's a near-certainty SoCal will get M6 aftershocks, 9% chance you'll experience an earthquake larger than the M7.1
Q: How bad was this earthquake?
A: A shakemap captures intensity, how severe we expect shaking to feel at the surface.
This was a major earthquake. We got lucky on location.
A: A shakemap captures intensity, how severe we expect shaking to feel at the surface.
This was a major earthquake. We got lucky on location.
All hail local reporting.
@latimes has a detailed description of how the earthquake felt and current damage:
latimes.com/local/lanow/la…
@latimes has a detailed description of how the earthquake felt and current damage:
latimes.com/local/lanow/la…
We classify strike-slip earthquakes by if you’re standing on one side, does it look like the other moved left or right?
This one moved right (dextral):
This one moved right (dextral):
Q: Erm, so about falling into the ocean...
A: Continental plate “floats” above denser oceanic plate, so our land is staying up here.
But in subduction zones (PNW), the plate buckled as stress builds, then slaps down & our. You get coastal submergence
A: Continental plate “floats” above denser oceanic plate, so our land is staying up here.
But in subduction zones (PNW), the plate buckled as stress builds, then slaps down & our. You get coastal submergence
Q: How do you evacuate with no car?
A: If a city issued evacuation orders, they’re also going to include dedicated buses for people who can’t drive.
But yeah, there’s still barriers (blogs.scientificamerican.com/observations/d…). Check on your neighbours.
A: If a city issued evacuation orders, they’re also going to include dedicated buses for people who can’t drive.
But yeah, there’s still barriers (blogs.scientificamerican.com/observations/d…). Check on your neighbours.
Q: Ugh, this is what people deserve for living in California.
A: Nope. No, you do not get to do that near me. Find your compassion and try again.
Everywhere has disasters. It’s a question of which ones you’re comfortable with.
I pick earthquakes over tornadoes. You do you.
A: Nope. No, you do not get to do that near me. Find your compassion and try again.
Everywhere has disasters. It’s a question of which ones you’re comfortable with.
I pick earthquakes over tornadoes. You do you.
Q: Did you goof your math?
A: Probsbly. It’s been a long few days & tweets don’t have an edit button.
1 step up in magnitude is 10x bigger & 32x more energy released.
Play with: earthquake.usgs.gov/learn/topics/c…
Read: earthquake.usgs.gov/learn/topics/h…
A: Probsbly. It’s been a long few days & tweets don’t have an edit button.
1 step up in magnitude is 10x bigger & 32x more energy released.
Play with: earthquake.usgs.gov/learn/topics/c…
Read: earthquake.usgs.gov/learn/topics/h…
So seiche are REALLY COOL.
They’re resonance waves, the water equivalent of playing on a swing. Resonance depends on size, so a wineglass, bathtib, pool, lake, or bay will have different frequencies.
They’re resonance waves, the water equivalent of playing on a swing. Resonance depends on size, so a wineglass, bathtib, pool, lake, or bay will have different frequencies.
Q: New Madrid?
A: I’m going to stay focused on West Coast seismology for this week, but I’ll totally do explainers on it next week if you remind me.
For now:
A: I’m going to stay focused on West Coast seismology for this week, but I’ll totally do explainers on it next week if you remind me.
For now:
Q: I have disabilities & I’m uncertain what to do.
A: Unfortunately, disasters aren’t fair. During major catastrophes that take down a region, community resources will be scare.
Make plans based on your lowest functionality. Plan 4 people deep for help. Have meds for 2 weeks.
A: Unfortunately, disasters aren’t fair. During major catastrophes that take down a region, community resources will be scare.
Make plans based on your lowest functionality. Plan 4 people deep for help. Have meds for 2 weeks.
Q: I’m broke & can’t afford to prep.
A: Money makes resiliency easier (supplies, ability to evacuate, retrofit, less marginal land, higher tax base for response...), but you don’t need cash to drill (Drop! Cover! Hold!) & to make a plan.
Build a kit from what you have already
A: Money makes resiliency easier (supplies, ability to evacuate, retrofit, less marginal land, higher tax base for response...), but you don’t need cash to drill (Drop! Cover! Hold!) & to make a plan.
Build a kit from what you have already
Q: Is having a bunch of earthquakes in one place normal?
A: Yes.
It’s extremely common (effectively always) to have aftershocks of gradually decreasing intensity & frequency. Remember our puppy-pile!
Foreshocks before a bigger main quake are less common, but not too rare.
A: Yes.
It’s extremely common (effectively always) to have aftershocks of gradually decreasing intensity & frequency. Remember our puppy-pile!
Foreshocks before a bigger main quake are less common, but not too rare.
Prep for your pet! But during the actual quake, stick with Drop! Cover! Hold on!
Unless you’re coincidentally already hiding your pet, you’re better off waiting until after shaking stops to check on them.
@apukwa gave good details & resources in replies.
Unless you’re coincidentally already hiding your pet, you’re better off waiting until after shaking stops to check on them.
@apukwa gave good details & resources in replies.
1. This is the cutest drill ever.
2. Puppies & earthquakes is totally our theme this week.
2. Puppies & earthquakes is totally our theme this week.
Q: I am anxious and freaking out and scared. Help?
A: That's totally valid. Disasters are stressful! You've been through a major event (& keep getting aftershocks!). It makes sense you need to debrief and talk it out.
Mental health resources:
A: That's totally valid. Disasters are stressful! You've been through a major event (& keep getting aftershocks!). It makes sense you need to debrief and talk it out.
Mental health resources:
Q: Are these earthquakes the start of a volcanic eruption????
A: No. These earthquakes are following an aftershock pattern, not a pre-eruption pattern.
If you’re concerned, check @USGSVolcanoes. Details: volcanoes.usgs.gov/volcanoes/coso…
A: No. These earthquakes are following an aftershock pattern, not a pre-eruption pattern.
If you’re concerned, check @USGSVolcanoes. Details: volcanoes.usgs.gov/volcanoes/coso…
All sorts of events produce seismic waves. Geophysicists are really good at prying them apart.
Details (in the context of nuclear tests & teenage sex):
bbc.com/news/world-asi…
I also did a @NerdNiteYVR talk on this last month; I’ll try to find a video.
Details (in the context of nuclear tests & teenage sex):
bbc.com/news/world-asi…
I also did a @NerdNiteYVR talk on this last month; I’ll try to find a video.
Q: Hah. Hah. Hah. His how am I supposed to get 2 extra weeks of medication?!
A: It’s going to depend on doctor & insurance, but you can sometimes make headway by citing official emergency preparation guidelines like those put out by @FEMA or @Safety_Canada.
A: It’s going to depend on doctor & insurance, but you can sometimes make headway by citing official emergency preparation guidelines like those put out by @FEMA or @Safety_Canada.
Are you ready to learn about soft stories?
US seismic codes are good enough we mostly don’t worry about collapsing buildings.
The exception is weak walls(garages, big window walls) or few interior walls (parking towers, open concept offices, malls)
US seismic codes are good enough we mostly don’t worry about collapsing buildings.
The exception is weak walls(garages, big window walls) or few interior walls (parking towers, open concept offices, malls)
Q: Where do I shelter if I’m in a building with a soft story?
A: Try to get it retrofitted BEFORE the earthquake to better resist shear. External bracing is stylish!
But if that’s not an option?
Shelter near the interior/most intact walls. Assume that open part will collapse.
A: Try to get it retrofitted BEFORE the earthquake to better resist shear. External bracing is stylish!
But if that’s not an option?
Shelter near the interior/most intact walls. Assume that open part will collapse.
