and random noise form Live Meteor:
runs my Random Number Generator....
The random numbers are generated in real-time in our lab by measuring the quantum fluctuations of the vacuum.
...and a good reminder to make sure your water heater / stacked laundry / fridge / etc is tied down properly...
> The Blanco Fault Zone is a transform, or strike-slip, boundary; that means it's where tectonic plates slide along one another. The most dangerous and powerful faults are usually seen in subduction zones, where one plate dives beneath another.
I was initially concerned about tsunamis - but this implies they don't occur on these types of fault lines.
...still... it's a good excuse to take a moment to think about preparedness. If you live on the coast - consider the most efficient inbound evacuation routes.
This is what's responsible for "megathrust" earthquakes on the west coast every 400-600 years. It seems we're early for one of those, so this is probably not that. I'd love to see more info on the significance, if any, of this movement.
If/when the Cascadia superquake kicks off, everyone will be passing that link around, so you may as well read it now.
Do some of that.
I live in Christchurch, New Zealand, and there were some obvious deficiencies in planning before the 2010 quake, and some obvious fixes were done after the 2010 quake. The main problem is convincing the cynical private and public that some prevention is worth paying for. Also the statistical victims are often not those that are making the financial choices.
>Kenneth Murphy, who directs FEMA’s Region X, the division responsible for Oregon, Washington, Idaho, and Alaska, says, “Our operating assumption is that everything west of Interstate 5 will be toast.”
"Until 1974, the state of Oregon had no seismic code...seventy-five per cent of all structures in the state are not designed to withstand a major Cascadia quake..."
"The shaking from the Cascadia quake will set off landslides throughout the region—up to thirty thousand of them in Seattle alone...Fifteen per cent of Seattle is built on liquefiable land, including seventeen day-care centers and the homes of some thirty-four thousand five hundred people..."
"On the coast, those numbers go up. Whoever chooses or has no choice but to stay there will spend three to six months without electricity, one to three years without drinking water and sewage systems, and three or more years without hospitals..."
In the situation you're describing, you're certainly correct that it's easily carried insurance. Although I'd leave the shovel. The ground is already going to be so toxic that a little bit of poop on the way isn't going to even be noticed. Might as well save the weight in the pack.
I feel like you're describing a "stay bag."
...there are the full-fault (M9) and partial-fault quakes (M8) , and the smaller ones happen more frequently:
>The Cascadia Subduction Zone has not produced an earthquake since 1700 and is building up pressure where the Juan de Fuca Plate is subsiding underneath the North American plate. Currently, scientists are predicting that there is about a 37 percent chance that a megathrust earthquake of 7.1+ magnitude in this fault zone will occur in the next 50 years.
This is not something I planned for when I moved to the PNW 25 years ago. But maybe I'll start trying this. Thanks for the protip. :)
If (e.g.) everyone in a small area reports strong shaking, while those in surrounding areas report less, that can indicate a need for further investigation as to whether the area that experienced strong shaking poses a specific risk.
Yes, a lot. They only have so many seismographs. They ask a bunch of survey questions that get them a pretty good qualitative score of the experience in your exact location, and when merged together gives them a much better picture of how the waves propagated.
Also they ask you questions about damage, which they can't get from anywhere else.
I don't know how precise iPhone accelerometers are, but modern seismometers measure on the nanometre scale.
There's also the issue of orientation. Seismometers measure X, Y and Z and are fixed in place, aligned with latitude and longitude or at an offset. It looks like you can get X, Y, Z from an iPhone accelerometer, but the phone could be in any number of different orientations. It would be necessary and difficult to rectify all those different orientations, as calculating magnitude on a horizontal or vertical component makes a difference.
Seismometers also have well known transfer functions, which are required because a step in calculating most magnitude types is simulating them as a particular type of seismometer, e.g. ml or local magnitude is taken after simulation as a Wood-Anderson seismometer.
Not saying it couldn't be done, just lots of problems to solve. There's always https://raspberryshake.org/!
Precision can to some degree be made up for by quantity. If data from all the phones in an area skew the same way, it can stand out even if the signal would be impossibly lost in the noise from a single detector.
More problematic would be calibration. A phone at the top of a tall building vibrating like a tuning fork is going to have a radically different signature from one at the same altitude but in the pocket of a mountain climber, which in turn is going to be very different from one at sea level but close to a highway. If you had a sensor sitting in the same place for a long time, you could probably characterize it, but assuming these are phones people are going to pick up and move after a couple minutes I doubt you could do more than a very crude guess.
I have only had the early warning go off once, and before I could act the quake hit. It happed to be really close, so not much warning.
It was a magnitude 4.3 approximately 20 miles away.
Yes, I did file a DYFI report. :)
It's been a long time since I was current in geology. I could be wrong. Our understanding of the world just keeps growing more complicated.
I have another map that may put some of it into perspective.
That is a mouthful if you had to say it but it works out to be the locations of every event with a magnitude greater than 4.5 since Jan. 1, 2018 in the map area defined by the coordinates in the link (basically bounded on the east by the Nevada border, on the south by the California/Mexico border, on the north by the northernmost quake in Idaho, and on the west by the plate boundary where we see the new activity.
Notice all the events along the California/Nevada border. Most of those are related to the July 2019 Ridgecrest earthquake which was a magnitude 7.1 event preceded about 34 hours earlier by a magnitude 6.4. Since that event, the faulted zone from Ridgecrest toward Mammoth Lakes and on to Carson City has seen increased activity that propagates from south to north and that has reactivated the east-west fault that runs east of Mono Lake into Nevada. Over time, probably the next few years, you will likely see similar quakes between Carson City and Medford, Oregon along that zone. That appears to be the eastern end of the plunging plate where we see the current quake swarm if you trace it out. (The edge may be near Yreka/McDoel CA area in the Cedar Mtn Fault System where the main faulting along the eastern Sierra/Cascades takes a more northerly turn.
Remember that the red squiggles are mapped faults and that they are actually continuous in the subsurface along zones of faulting that follows the general squiggle trend.
The latest activity on the transform fault offshore just continues that older trend (grey dots are events that have happened since Jan 1, 2018 and that are more than a month old) out to the western edge of that plate.
Interesting stuff. I'm not a seismologist, just a geophysicist. This stuff interests me as I like to look for patterns in life. Don't use any of this in any official capacity. Follow the science and take everything in this post as a simple description of one person's observations of events and data in one geographic area that probably could be interpreted in multiple ways, even by the same person. As such this is meant to entertain, not to inform.