Did the Earth move for you?

By Phil Plait | August 2, 2006 8:28 pm

It just did for me.

We just had a magnitude 4.4 earthquake here in NorCal, with the epicenter less than 5 miles from here. For those of you on solid ground, a 4.4 is just under the borderline of being scary. Things shake, but it’s unlikely anything will get knocked over. Nothing did here.

Mrs. BA and the Bad Dog were at the park, with the Little Astronomer about to go when it hit. I thought LA was jumping in the next room! After about a second it was clear what was happening. It was very short, just a rumble, then the peak shaking for less than a second, then it was over. Heart thumping, I ran into the living room, and LA was saying "earthquake!" (it was her first that she felt; she slept through the other sizable ones we had a few years ago).

Everyone here is OK, but man, there’s my cardio for the day!

Update (about 20 minutes after the quake): Mrs. BA came home and said that outside at the park (like 200 meters away) they could feel it much better. She said it was like a wave coming underneath her, and she could feel herself lifted up a little bit! Wow, that must’ve been cool. The Bad Dog ran around and barked, too, so at least we all got to enjoy it.

Comments (34)

Links to this Post

  1. girl-puertorico | August 3, 2006
  1. Jamie

    Glad everyone is okay, that’s one thing I’ve never experienced. I live in Ohio, we have earthquakes, but nobody knows it.

  2. When you do, you’ll know. The New Madrid fault is scary, and I live a few minutes from San Andreas.

  3. I always asked my self; why do people choose to settle in areas where natural disasters are known to happen?
    Then later I found my self living in Darwin, Australia, preparing an emergency kit and to evacuate down south because a hurricane warning had been issued.

  4. I felt it here in Sausalito. It felt like someone jumped on my roof – I looked outside, saw no one on the roof, and so figured it must be an earthquake.

  5. Pyrocat100

    Felt it in Southern Santa Rosa. Sort of hard to tell what was happening at first, because there was a big boom noise and then I noticed the ground was shaking, then I realized “earthquake”. My cat was totally freaking out. I was laughing afterward because an earthquake hasn’t happened in SR in a while. Boy was that a jumper.

  6. Yeah, it was loud, wasn’t it? Pyro, you’re not terribly far from me, and it was loud here. It’s been a long while since the last one.

    And Thomas, look at a map of the US and tell me where there isn’t a natural disaster looming. Earthquakes and fires out west, drought and tornados in the midwest, hurrcanes in the southeast and east, blizzards in the north and northeast. The northwest has the odd volcanic eruption, and I think the issues with Hawaii and Alaska are self-evident.

    And don’t forget the New Madrid fault. Yeesh.

  7. Yeah BA, that’s what I mean, the world is full of them. It’s just because I’m from snug safe little Denmark were the only natural (and unavoidable) disasters is high taxes…..

  8. fjordan

    Yeah, I live in Memphis, Just about 70-90 miles from the New Madrid zone. I keep watch on any activity on a USGS site http://earthquake.usgs.gov/eqcenter/recenteqsus/
    As long as there’s small quakes 1 to 2 in magnitude, I surmise that the zone isn’t building up enough energy for a BIG quake. However, when I don’t see any activity for several days – that worries me since the New Madrid is not a ‘slip zone’ like the San Andreas

    On the other hand, Most of California and the Aleutian(SP?) penisula are popping all the time as can been seen on the above site.

  9. Shawn S.

    Must have been a delayed seismic event caused by World Jump Day. Those dastardly hippies!

  10. Evolving Squid

    As long as there’s small quakes 1 to 2 in magnitude, I surmise that the zone isn’t building up enough energy for a BIG quake.

    If there was a Bad Seismologist, he’d probably have a web site with that topic on it.

    It would take tens to hundreds of thousands of magnitude 1 and 2 earthquakes to quietly release the energy of a magnitude 6 earthquake. That large level of seismicity is simply not observed. So you could have a hundred magnitude 1 earthquakes today and 10 magnitude 2 earthquakes tomorrow, and still the fault could hand you a prize-winning magnitude 6 or 7 the next day to rearrange your living room furniture. And a 6 isn’t really all that strong in the great grand scheme of earthquakes.

    To put it in perspective, imagine your bathtub is full of water. That water represents the energy that would be released in a magnitude 6 earthquake. A standard bathtub is about 600 litres. Empty the tub with a shotglass – that’s about how many magnitude 2.5ish earthquakes it would take to stave off that magnitude 6. Realistically, the tap is trickling while you’re emptying.

    Use the shotglass on 10 tubs full to scale to a magnitude 7.

    And if you want to simulate conditions in a subduction zone (like the west coast), do it to 1000 tubs, with the tap on full and if any tub overflows, they all catastrophically empty as a magnitude 9 megathrust earthquake.

  11. Well, that about says it, doesn’t it?

    Yikes.

  12. TheGalaxyTrio

    Pfft! Amateur! ;-)

    Here in So. Cal. we don’t even get out of bed for anything less than a 6.8

  13. Supernova

    Did you check it out on the USGS website? They have a cool earthquake tracker page. You can even report your own “observations,” and see “shake intensity maps” that show how far away it was felt. Your quake shows up as a big blue square, with a couple of tiny blue squares representing aftershocks. Fun stuff.

    Maps of Recent Earthquake Activity in CA and NV

  14. diederick

    I used to libve in the north of the Netherlands, where the only earthquakes are caused by pumping gas out of the ground. They’re only little ones (no one even talks about richter scales) but you feel them nevertheless.

  15. Lux

    Felt it out by the USCG base near Two Rock. Scared the bejeezus out of my parrots.

  16. Dan Gerhards

    It just moved for ME too–in southern Washington state!

    At 1:40am Thursday, there was a short quake. I’m guessing 3.5, but I’ve only felt three quakes and don’t have much to go on. It bounced us several times; it didn’t feel wavy. Even a small one scares me for a bit because we have several semi-active volcanoes nearby.

    You heard it here first!

  17. Dan Gerhards

    More on *my* earthquake:

    USGS says it was a 3.8 with the epicenter *two miles* from my house! I had figured it was a bigger one farther away, maybe under the infamous Mt. St. Helens, but no. That must be why it was sharp and “bouncy”–it was right next door.

    (Thanks to Supernova for the USGS link.)

  18. Kullat Nunu

    Sounds really exotic to us who live on Precambric shields — never earthquakes here!

  19. Evolving Squid

    We had a 4.5 here in Ottawa in February (despite being on precambric shield :) it’s an active seismic zone that baffles seismologists a bit… the universe hates bureaucracy I guess… Isn’t DC on a fault too?). What was cool was that it had a fairly shallow hypocentre and the epicentre was about 40 km east of me, so it was really easy to feel.

    At the time I was talking on Teamspeak with a friend in Montreal and another in the east end of Ottawa (I live sort of west). So the guy in the east end said he felt shaking, and about 2 seconds later, I felt it, and we had time to tell the guy in Montreal, who felt it about 15 seconds later.

    My wife was out camping with her Girl Guide troop, and they didn’t feel a thing.

  20. Karnalis

    Heehee. “Bad Dog.” That amuses me immensely. :) I wonder if the Bad Dog debunks common dog-related misconceptions…about dogs. Man, it’s too early…

  21. icemith

    Um… I desperately want to contribute to this blog, but there have been no earthquakes here in Sydney, Australia, nor have we felt yours. I don’t know if there was any mention on our evening news, but then it was a relatively slow news day.

    Phil, you mentioned all the possible danger spots in the States, bar one. Considering the recent topics, I’m surprised you didn’t include looking above. I mean the menace of Asteroids!

    And to TheGalaxyTrio, I reckon you really wouldn’t have to get out of bed for a ’10 tubber’, as it would toss you out itself, maybe along with your roof!

    Though over the years I have felt at least two worrying ‘quakes here, I certainly knew what they were, the worse one causing considerable damage a hundred miles north in Newcastle, but that was about twenty years ago. I checked out the Earthquake map link mentioned above, but before closing it, had to have a look at our little area in Australia, and so far it’s clear, and hoping it stays that way. Quite reassuring really.

    Ivan.

  22. I’m in Portland OR, and was awakened by that 3.8 in Battle Ground WA. It felt like someone drove their car into our home, actually.

    We get “noticable” earthquakes once or twice a year in this part of the world. It’s sort of amusing.

  23. Chris Louth

    Evolving Squid: Those two comments are great – the bathtub analogy will get passed around here for the next little while.

    The Teamspeak comment is probably the most interesting earthquake-related comment I can recall seeing in any forum though. The Internet was designed (intelligently!) to withstand all sorts os stuff, but I doubt that the ARPA ever expected live Teamspeak commentary across time zones during an earthquake.

  24. I was in Boston when a magnitude 3.9 quake hit my hometown of Huntsville, Alabama. I also happened to be in Boston when a lightning bolt struck my family’s home (more precisely, it hit a juniper tree out back, arced to the rain gutter, blew out the vinyl siding, coursed down the telephone wire, fried the computer and set the house on fire). Fortunately, my family was away on a geneaological research trip, so nobody got hurt, although I’m sure the cat was incredibly disturbed.

    Back in 1989, my father and I were caught at ground zero of the F4 tornado which struck Huntsville that November. We had gone to the plumbing store to buy parts to fix some broken household appliance — driving in my father’s canvas-roofed Jeep. Guess where the twister decided to touch down?

    We were parked right next to a fire station. With the wind howling past, in what I remember as very deep darkness (it wasn’t even five o’clock), we saw the fire trucks go barreling out of the station, their sirens operating full blast. Later, we learned that the firemen had seen the funnel cloud suddenly illuminated in a flash of lightning and realized their best course of action was to drive for their lives. I’m glad we followed them.

    Dad worked for the Huntsville Times, so we went back to their offices. It was a cool experience to sit in the news room and watch the disaster reports come in from across town. Deeply unsettling, but very cool nonetheless.

    After staying up all night, my parents let me skip school the next day: a little joy amidst the general trauma of a natural disaster. Never say I’m short in the macabre humor department. . . .

  25. tjm220

    Nothing too exciting in Calgary to report but I have experienced the floor (27th at the time) in my office tower shake noticeably for a few seconds.

  26. Gary Ansorge

    Having been born and raised in Los Angeles, I am so familiar with ‘quakes, I can estimate the intensity within plus or minus .3 Magnitude.
    Currently living in Georgia, the biggest thing around here are thunderstorms and they can be really big. Seen lightening strike 30 feet away. Now THAT’S scary!

    Gee, so many ways to really mess with someones real estate so, remind me again, why are planets a good place for our techno civilization?
    I know, they’re great for RAISING life, I just see little use for them as a safe place for technological civilizations. Space colonies seem much better.

    Gary 7

  27. bearcub

    I missed it here in San Jose. I was on the road at the time and a 4.4 wouldn’t be enough to notice while driving.

    I’ve pretty much lived in San Jose my whole life, so missing a couple of small ones is no big deal. They don’t really get fun (to me) until they get to 5 anyway. I know, I’m weird.

  28. Tim G

    I experienced this earthquake while Bangor, Maine. I was at my father’s place the day after Thanksgiving. The window pane began to rattle. At first I thought that a truck was going to drive by, but none did. Then I noticed the chandelier swinging overhead. I was surprised that such a quake could be felt in Maine, far away from where I thought fault lines were. I heart that the earthquake was due to the earth rebounding upwards due to glacial retreat at the end of the last ice age.

  29. Tara Mobley

    Completely slept through it, unless it wasn’t felt this far South. It’s possible. 4.4 is kinda tiny, and this seemed to be centered in Santa Rosa.

  30. Nigel Depledge

    I’m in the same boat as Thomas Siefert, as ’twere… here in the UK, the only disaster we have is our elected leadership.

    No earthquakes, no hurricanes, no tornadoes, no volcanoes, no serious blizzards (or, maybe one every 10 years), widespread flooding is quite rare, no forest fires…

    Anyway, BA, why should anyone look only at the US to see natural disasters “everywhere”? Look at the globe as a whole – you have areas that tend to get natural disasters more often, and areas that tend to get very few.

    Anyway, can anyone amswer a question that’s been puzzling me for many years? In the US, with the hurricanes and the tornadoes in particular – why do they build all the houses out of wood?

  31. Hugh Jass

    Was at a friends in Petaluma when it hit. Fun enough size, ‘course got us all talking about how big it might have been where we thought the epicenter was. Turned on the news right away and saw it said “small quake in Glen Elen” well we all started guessing as to magnitude since it was pretty close. Myself and a fellow Geology Grad guessed about 4.5… just had to brag on that one, even if I’m the only one that thinks I’m cool.

    That is the sort of thing that gets me thinking again however. During college the big debate by USGS geologists was whether the next BIG ONE in Nor-Cal would be from the Roger’s Creek or Hayward fault, with a few ~ATM types saying San Andreas or Calaveras. Its good to see that popular opinion has settled on the one in my back yard http://quake.usgs.gov/research/seismology/wg02/ … or I guess technically speaking closer to the front yard.

    Bearcub… as far as driving and how big it has to be to feel I wonder, especially on a strike-slip type quake. I was down not too far (~35 miles) from the good sized (6.0) parkfield quake http://www.cisn.org/special/evt.04.09.28/ a couple years ago didn’t have a clue then saw a bunch of folks pile out of a building. I also knew a guy who was driving in southern Marin during the ’89 Loma Prieta quake and wondered why everyone on the sidewalk was bouncing around arms waving like a silly dance… he then stopped at a light while the shaking was going on and said it was the weirdest feeling as the car “rocked like he was parked on a waterbed.”

    Squid, that bathtub visualization maybe the best description for increasing magnitude I’ve ever heard. Just reciting numbers alone never really has the correct impact for most folks that need that much explaining… and many that don’t… on what a 100 fold increase in energy means. I’m stealing that for future discussions. ;)

  32. Max Fagin

    Well Mark Martin, there is a place in the US were FEMA shouldn’t have any interest. I live in Colorado Springs, CO. To far from the coast for a huricane, to far from the plains for a tornado, to far from the mountains for a serious blizzard, and clearly to far from any fault to be concerned.

  33. Space Cadet

    I didn’t feel it in Healdsburg – I haven’t felt one since Loma Prieta – but I know exactly where I was and what I was doing at 8:08: I was at bat suffering my first ever strikeout. Anyway, that’s my story and I’m sticking with it!

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