Why can't I use the back button on this website? It just goes back to the same site. I've noticed this behavior across other websites lately as well, is this a new design thing?
> 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.
I liked the previous title about the Monster of the Cascadian Basin. I looked it up (found nothing) but came across this on the cascadian subduction zone:
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.
More accurately, these quakes are on a strike-slip fault (named the Blanco Fracture Zone) on the other side of the Juan de Fuca plate from the Cascadian Subduction Zone. This fault won't directly produce 'the big one' but this movement will be building pressure and tension in the subduction zone.
Yes, that article is a classic, in the Venn diagram intersection of "hard science explained well" and "creative ways to get historical data" and "both local and federal government failure to plan or address known issues" and "we were warned" and "absolute nightmare fuel".
If/when the Cascadia superquake kicks off, everyone will be passing that link around, so you may as well read it now.
It's not up to me, so please temper that impulse to shoot the messenger. But retrofitting or even rebuilding homes, schools, hospitals, bridges, etc. would be a great start. Proactively holding more mandatory earthquake drills, not just in schools. Adding Earthquake Early Warning devices to schools, office buildings, power stations, transit (which would slow down or stop the train before the shaking starts). Adding more seismic sensors to the currently very sparse Early Warning network, to get better data and therefore better predictions and more warning time to people living away from the epicenter; even ten or fifteen seconds of warning could prevent some injuries.
Look at what first world countries do just after major earthquakes.
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..."
A 'go bag' containing enough food to survive months would be rather unwieldy to carry around. Hopefully it survives the initial earthquake in an accessible location so permit bugging out. However, its not much use if the house has collapsed or you're stuck at work.
Ah, I misunderstood. I was thinking someone was trying to make it through to the other side without leaving.
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.
Somehow I don't find that too reassuring, even though I am several miles east of I-5... but my house is new construction, and had to pass seismic inspection, so there's some hope.
>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 my favorite way of blowing off adrenaline after an earthquake. It's also fun to watch the reports roll in and see how different areas were affected.
https://earthquake.usgs.gov/data/dyfi/ USGS' "Did you Feel it Program" helps USGS figure out how seismic waves travel through the crust, which isn't uniform in density. Useful beyond seismographs.
Sure, they have seismographs, but they don't necessarily have full details on all the subsurface geology between you and the epicenter. Wave propagation can be complicated... depending on what's down there, the waves can intensified, dissipated, reflected...
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.
> Does human reporting add resolution or other information to their data?
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.
With a standardized report format the data can complement modelling of ground motion intensity caused by an earthquake, such as https://earthquake.usgs.gov/data/shakemap/
I'm not an expert in seismometry, but I think there'd be quite a lot of challenges to overcome. Off the top of my head:
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.
Orientation wouldn't be that hard an issue to overcome, phones have magnetometers to act as a compass, and accelerometers which indicate the direction of gravity, so assuming you have a decent idea of where on earth the phone is located, you can work out its orientation in 3 space.
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 got a second or two of warning once (also a fairly nearby quake). It's really odd to know in advance. Also used MyShake for a DYFI report just last night.
How would you distinguish between seismic events and someone walking by, running up and down stairs, or just bumping the table the phone is sitting on? seismometers are strategically located in places where humans won't accidentally affect their readings via normal daily activities.
You'd have to do some heavy filtering of the data while taking into account neighboring phones. I have no idea if any of this would work but it _could_ be really interesting to see.
As I recall it, transform "faults" are not really faults. They are the traces left between moving spreading centers. They can be weak zones and be the center of volcanic activity. Magma moving toward a potential eruption is my thought.
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.
This is a continuation of fairly normal activity along that plate boundary of the coast of Oregon. I have watched this whole area for a long time just for grins.
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.
and random noise form Live Meteor: https://meteorscan.com/meteor-live.html
runs my Random Number Generator....