Hours. Hours beforehand. Having that much preparation would be life-saving. Especially for us living near the Cascadia Subduction Zone.
This report, maybe, but even the article includes links to previous ones which have.
Here’s one, but if you click through to the project’s website you’ll find more.
Because there are also a million other correlations with the earthquakes which are just coincidences.
That said, there is interesting work in geology to more accurately characterize this mechanism. The last paper I saw was reference in Science News indicated that pressure on granite (which has a peizo-electric effect) might be the underlying mechanism. I haven't seen any follow up on that hypothesis though (proving or disproving). It would seem pretty straight forward for the seismograph sensor makers to add an E field strength meter to observe this effect if it occurs.
With current best-effort science it’s basically impossible to detect them ahead of time, particularly with any relevant geographic accuracy. At most only a probability figures within a 10-100yr+ range over a very broad area seems to be the best they can do. Fault lines can encompass hundreds of towns and cities.
Even if they detected the Cali quake before hand from Vancouver there is no way they could pin point that in any reasonable way to evacuate particular towns AFAIK.
Does this mean my cat is tuned in to ham frequencies? She was not right in the hours before the 7.1, and once the shaking stopped she was back to her normal self.
Did significant earthquakes ever occur when your cat was acting normally?
(http://www.chrispennello.com/tweller/ , page 38)
For a similar example, check out https://www.lightningmaps.org/?lang=en. They use inexpensive, freely colocated time of arrival RF receivers to triangulate lightning strikes across the world . It operates on a shoestring budget as a hobbyist project.
There might be no signal to be found, but it seems from a cursory glance that to investigate would be a low cost exercise.
Most of the EM based earthquake prediction is based on really loose reasoning. In summary, it goes like this: "earthquakes can generate EM fields through piezo-electric effect, therefore small movements before big earthquakes should generate small EM fields we can measure". But there is almost never no such thing as "small movements before big earthquakes", which is why reliably predicting them has been impossible so far.
Most likely, this will turn out to be an example of confirmation bias. In the unlikely event that it is not, people will be all over this.
We don't have a full mechanism to explain them (or, rather, there are a lot of competing mechanisms that don't fully explain things). More importantly, precursors don't seem to occur consistently as you noted.
However, they're also not worth automatically dismissing. The idea that they're all a simple case of confirmation bias has been extensively discussed, and while it's not currently possible to refute, it's starting to seem less likely. There's certainly been a lot more attention given to possible precursors and mechanisms in the last 5 years than there were before. It's a serious avenue of research right now. Keep an eye out then next time you're at AGU. I guarantee you you'll see at least a few posters around possible precursors and/or precursor mechanisms.
Forecasting is definitely pseudoscience, but EM-related precursors are a fairly hot (and controversial) research topic at the moment.
It's not pseudoscience because it can be disproven--which is generally what happens.
The issue that everybody forgets is that predictions have FOUR outcomes, not two.
You have the one everybody remembers: "I predicted X and X happened".
You have the one some people remember: "I didn't predict X and X didn't happen."
You have the one that people rarely remember: "I predicted X and X didn't happen."
You have the one nobody remembers: "I didn't predict X, but X happened."
The problem is that for rare events, the "predict X and not X" and "didn't predict X but X" have to be REALLY low probability for a measure to be useful.
Predict X and not X is a huge issue though, as you suggest.
There were some reports of earthquake lights and earthquake clouds recently.
There's some online communities dedicated to those, e.g. https://quakewatch.net/predictioncenter/
Edit: I mean accurate forecasting and prediction using this data is pseudoscience.
““The earthquakes show up as RF noise because of the electric field lines, now scientifically confirmed to change the way the ionosphere reflects RF,” Schwarz said.
Schwarz has cited an article in the October 2018 edition of Scientific American, which, he says, explains the phenomenon. (See Erik Vance’s “Earthquakes in the sky,” Scientific American, October 2018, p. 44.)“
There's some overlapping between some online communities I participate in and the doomsday preppers/tracker community so that's why I stumbled on this.
The Wikipedia page for Earthquake Lights talks about lights as far as 740 km from the epicenter, so I'd bet that's the answer people who associate those with the quakes will tell you.
As I said take it with a grain of salt.
Last I read about the alleged phenomena, you're supposedly looking for straight line or ripple clouds that form in seconds. The explanation is that some mechanism (originally friction) is boiling groundwater; but proponents can no longer agree on what mechanism leads to formation of the clouds.
Supposing there were enough water vapor to do that, how would boiling groundwater form clouds at all, much less in seconds? There's still a lot of earth in the way between the fault and the sky.
Ground shaking does not mean that energy is converted into heat. Does the ground feel hot after an earthquake? Warm at all?
Earthquakes, right? Not volcanoes or magma chambers? If this phenomenon were real, wouldn't you expect it to occur right before a volcanic eruption, which actually involves large amounts of magma, near the surface, which could actually vaporize large amounts of groundwater? As far as I can tell, that doesn't happen either. The water vapor erupts with the molten rock, and mainly condenses into volcanic clouds because it has volcanic particles to condense around, not because the water vapor itself is enough to form clouds on its own before dissipating.
I worked on a project at Stanford that set up EM sensors around the bay area to possibly detect signals before major earthquakes.
I mean, right now it's all purely hypothetical but it's absolutely worth trying to find it if it's there, and compeltely within the realm of worthwhile science.
There have been all kinds of tests with animals but so far, all animal behaviour that looks like predicting earthquakes is only their sensitivity to low amplitude-high speed P (pressure) waves, which humans usually don't feel.
It seems to trigger a flight reflex, it makes them take off real fast. I use a high voltage arc generator to scare pigeons off my deck. The sound from the arc seems to trigger the same response. It is certainly much more effective than yelling at them or waving one's arms around.
There's evidence for real prediction, including reports of a ramp up EM energy a day before a quake.
It could be a coincidence, but reports of animals acting oddly before quakes aren't uncommon, and we've recently found a plausible biological basis for how birds sense magnetic fields, so some animal or animals may be able to detect signs that an earthquake is more likely to occur.
I don't understand. What would a possum do instead if there was no earthquake? Stay on the house? Walk out into traffic on a highway?
During daytime? Yes, mostly, IIRC, they are nocturnal and come down during the day mostly when in food distress or disturbed.
But, of course, if you saw a possum come down (perhaps from hunger, or because a crow dropped a husk on it and disturbes it, or whatever) without a near-following earthquake, you might say “Hmmm, odd”, but it wouldn't be a major notable event. But two uncommon events near in time get linked mentally, even if there is no relationship.
No offense but talk to people who have had "psychic readings" performed and plenty of them will swear to you that psychics are, in fact, 100% real.
People have researched ESP and debunked it. Currently, we are still researching earthquake prediction.
No one is claiming anything supernatural is occurring, of course. There may be real changes in the earth's crust before earthquakes which send out signals we haven't yet found.
With animals, we have no clue why there appears to be a tendency for them to act oddly before an earthquake, and up until recently, we didn't understand how birds could navigate as effectively as they do.
It's possible that what we see with animals is just coincidence or an artifact of how we perceive our own memories after traumatic events, but it's also possible that an animal or some set of animals can perceive something associated with certain earthquakes.
It would be far more likely that the EM pulse happens with slightly faster propagation than the kinetic pulse (like milliseconds, not hours).
The last decent one I can remember was a few years ago around maybe 2 or 3 AM and made my apartment roll back and forth. The rolling woke me up but my partner slept through it. And I tried not to panic so they could just sleep through it, hoping it would end soon.
Also, we didn’t have anything hanging or that could easily fall onto our bed in the bedroom so I think staying in the bed was an okay move.
I live in a single family home now even higher up the Twin Peaks area of SF so who knows how this house will handle the next one. Hopefully it won’t be too bad. At least the ground is solid and not considered a liquefaction zone. And my new neighbors seem to have some kind of thing going on where they stock first aid supplies for first responders in disasters which seems nice and thoughtful.
Though I just don’t understand why SF won’t use our missile warning system for earthquake warnings. Seems like they could make a special earthquake tone and warn everyone if one happens in another city and is heading our way. Even seconds of warning would be so helpful. Could be the difference in being able to jump under a table or desk vs. getting crushed by falling stuff.
Perhaps one of the first two waves woke you up, and then the surface wave is what "felt" like an earthquake to you.
In fact, earthquake warning systems detect P-waves early, send out alarms, and give people a few seconds to stop subways and get outside before the surface waves roll in. It's not the same as earthquake prediction, though.
On more than one occasion, I think I've anticipated an earthquake based on sound. I can only describe it like an approaching but amorphous activity, a bit like when large flocks of birds take to flight over an open field or when a wind gust goes through a forest.
I think I've noticed this sound only with relatively nearby epicenters (5-25 miles). The very distant ones usually seem more silent and my first recognition is the jiggle and displacement, or perhaps the creaking sounds of the surrounding structure if I am indoors.
For those who don't know, PSK reporter is a system for logging propagation reports using digital modes like PSK and FT8, mostly on HF amateur bands (incl. 80,40,30m).
You might expect to see some kind of effect on July 4 if this effect were as widespread as described in the article, but to my eye it looks like a normal day.
What makes it interesting here is that it's a frequency range that is commonly-used and that also propagates in modes other than line-of-sight. For instance 'groundwave' propagation curves around the Earth because of induced currents in the Earth.
This allows HF communication over the horizon. Enthusiasts are regularly able to make contact between continents with amplifier power of less than 5 Watts.
For most of the HF spectrum reflections off the ionosphere are the main useful propagation mode. At the short end (like CB radio) bouncing of the ionosphere is harder so line-of-sight is more common.
As for the purpose of weakening earthquakes, this energy may as well have already left the system - it's propagating away from where the problem is. This article is like saying that exhaust from a car engine decreases air quality. You could harvest that exhaust but it won't affect the engine. If somehow you did have enough pressure and containment to keep the exhaust from leaving the engine at all, that would have some effect. But if we could do that EM fields over all of California, I think that would have bigger effects on the planet than weakening the occasional earthquake. That's like a Star-Trek-level of control over a planet.
I always thought lightning bolts had something closer to a megawatt-hour, so thanks for clearing that up for me!
A lightning bolt lasts for seconds at best, so not sure why you’d think it’d provide megawatts for a duration of an hour. That would mean the instantaneous current would need to be much higher than a terawatt, which is several orders of magnitude higher than what it is.
Some people here are excited about hours... but this guy can detect these things DAYS in advance.
There was a time not so long ago when sprites, whistlers, jets, starters, ELVs and other TLEs were funny stuff. Today we understand that gammas are produced by thunderstorms. Times change.