ADVERTISEMENT

OT: Science! Also "heads up, California"

What a weird article. It starts by saying scientists are warning the big one is coming "any day now" and finishes by saying the small quake the other day isn't necessarily predictive of a bigger one being imminent.

Regardless, it's a matter of when out there, not if.
 
Any day now in geology means something different than normal usage I think.

No, it doesn't. Geologists routinely deal with expanded ranges of time that the rest of us generally don't consider, but they don't hyperbolize.
 
The little quakes do not relieve pressure. Hence it has no impact on the probability of the big one.
 
The little quakes do not relieve pressure. Hence it has no impact on the probability of the big one.

Faults, rather than being simple lines, are more accurately described as "fault complexes" and resemble trees - with the main fault as the trunk and many smaller faults appearing as branches.

Often these smaller quakes occur in the branched faults in the complex and, as such, can effect the strain on the main fault in any number of ways, either increasing it or decreasing it.
 
From what I've read "the any day now" is based off of past geological activity from the fault and not a prediction that it will actually happen tomorrow or next week.

From this article: http://sanfrancisco.cbslocal.com/20...ault-expected-any-day-now-fremont-earthquake/
“The past five major earthquakes on the fault have been about 140 years apart, and now we’re 147 years from that 1868 earthquake, so we definitely feel that could happen any time,” Brocher said.

Also a couple of pretty good replies to the question on reddit, https://www.reddit.com/r/askscience...geologists_say_an_earthquake_will_happen_any/

Any day now is kind of a relative term, especially when it comes to earthquake forecasting. We can't pin it down to an exact period of time, the assumption being made is that large earthquakes on this fault are vaguely periodic so the recurrence interval and time since last major event are being used to say that the probability of a large event in the near future is high (i.e. "any day now").

How do scientists go from geologic time scales to such tiny prediction periods?

This is based on our understanding of past earthquake activity on a fault and assumption about fault behavior based on this past record. By studying the geology near the fault (basically, by digging trenches across the fault and doing detailed analysis of the disruption of different layers and dating various layers) we can develop a chronology of past earthquake events. When we do this, one of the quantities that we are interested in is the recurrence interval, which is the average time between large events (the size of a "large event" being dependent on the fault, for some faults the largest event possible might be a M5, where as other faults might be capable of generating a M7, etc). Some faults are more periodic than others, meaning that the average recurrence interval is a good approximation of the time between individual events (or put another way, the standard deviation of all the times between events would be small).
 
Hyperbole is a media and message board specialty


Link
In a terrible example of fearmongering, numerous media outlets have repeated the headline that seem to say a USGS scientist, Tom Brocher, has predicted there will be a major quake in San Francisco in the next few days, as seen on the left of the above image.

Tom Brocher responded to this by saying "my comments have been misrepresented" and that the actual risk is "a 31% probability of a magnitude 6.7 or larger event in the next 30 years"

In other words, a one in three chance of a large quake some time in the next 30 years. Not "any day now".
The 31% number comes from a 2008 study. Reports in April 2015 showed the USGS had revised numbers downward to less the half of that. Still not fun to think about, but hardly 'any day now'.
 
No, it doesn't. Geologists routinely deal with expanded ranges of time that the rest of us generally don't consider, but they don't hyperbolize.
No. Im pretty sure they do. I really doubt, based on the article, that these guys mean, this will go off any time in the next few weeks.

Any day now to me means within the month. Do you really think the guy is saying between now and Labor Day there will be a relatively large earthquake on this fault. Or do you really think he means - sometime between now and 2020. Im guessing is closer to the later.

Edit: I should have read the rest of the thread - which clearly backs it up, in facts its even less dire than I thought they meant. Any day now, means, as it always does in geology, sometime in my lifetime.
 
Good clarification - thanks!

The Bay area is still overdue, I think.

But then, the Yellowstone caldera is overdue, as well.
 
No. Im pretty sure they do. I really doubt, based on the article, that these guys mean, this will go off any time in the next few weeks.

Any day now to me means within the month. Do you really think the guy is saying between now and Labor Day there will be a relatively large earthquake on this fault. Or do you really think he means - sometime between now and 2020. Im guessing is closer to the later.

Edit: I should have read the rest of the thread - which clearly backs it up, in facts its even less dire than I thought they meant. Any day now, means, as it always does in geology, sometime in my lifetime.


No, you're still wrong - because as it turns out, "The phrase "any day now" was only spoken by the reporter Andria Borba."
 
Media these days has a real hard time objectively reporting science news. They can't keep their penchant for drama out of it. Controversey is drama and drama is entertainment and entertainment SELLS! Real journalism is becoming an endangered species.
 
Without consulting the internet, anyone recall the most powerful earthquake in recorded history in the continental US?

Not surprising that the media sensationalized the geologist's comments. In general, science literacy is really low in the media and the general public, which is why so many people believe in ghosts, superstitions and completely untested/unproven herbal remedies (and think vaccines are dangerous).
 
  • Like
Reactions: RUforester72
Without consulting the internet, anyone recall the most powerful earthquake in recorded history in the continental US?

Not surprising that the media sensationalized the geologist's comments. In general, science literacy is really low in the media and the general public, which is why so many people believe in ghosts, superstitions and completely untested/unproven herbal remedies (and think vaccines are dangerous).

My guess is that it would be the New Madrid quake, which was... 1830s? 1850? It was prior to the invention of seismic measuring equipment but the general consensus is that it was 8+.
 
The earthquake during an Oakland-SF World Series in the 80s was pretty intense, with lots of damage, watching the Stadium literally shake before the cameras lost power is an image I'll never forget.
 
My guess is that it would be the New Madrid quake, which was... 1830s? 1850? It was prior to the invention of seismic measuring equipment but the general consensus is that it was 8+.
Winner, winner, chicken dinner...until I looked it up, lol. I always thought it was the New Madrid earthquakes in 1811-1812 and I also though the consensus was 8.3-8.4, but not according to the USGS, which has the three at 7.7-7.8, but has one in the Cascades and three in Cali ahead of these. Oh well.

http://earthquake.usgs.gov/earthquakes/states/10_largest_us.php
 
Winner, winner, chicken dinner...until I looked it up, lol. I always thought it was the New Madrid earthquakes in 1811-1812 and I also though the consensus was 8.3-8.4, but not according to the USGS, which has the three at 7.7-7.8, but has one in the Cascades and three in Cali ahead of these. Oh well.

http://earthquake.usgs.gov/earthquakes/states/10_largest_us.php

Yep. I just looked it up as well. I'm not familiar with the Cascades Thrust Zone quake but am skeptical of the 9+ estimate.

New Madrid made the town completely disappear and altered the course of the Mississippi River. That had to have been pretty cool.
 
I lived in Santa Cruz in 1985 but moved out of the area before the 1989 Loma Prieta earthquake 6.9 magnitude which hit the San Francisco area hard, 63 deaths. I went back to Santa Cruz after the earthquake and was sad that most of the downtown buildings, which was really old, were destroyed in the quake.
 
Without consulting the internet, anyone recall the most powerful earthquake in recorded history in the continental US?

Not surprising that the media sensationalized the geologist's comments. In general, science literacy is really low in the media and the general public, which is why so many people believe in ghosts, superstitions and completely untested/unproven herbal remedies (and think vaccines are dangerous).
You can say what you want about herbal remedies. All I know is that regularly taking alpha lipoic acid (a) keeps ghosts away - I haven't seen so much as one ghost since I started taking it, (b) causes uncontrollable sarcasm and pun creation, and (c) makes my dangly bits tingle.
 
Not surprising that the media sensationalized the geologist's comments. In general, science literacy is really low in the media and the general public, which is why so many people believe in ghosts, superstitions and completely untested/unproven herbal remedies (and think vaccines are dangerous).
Well, vaccines ARE dangerous - they cause autism, don't they?
SmileyPokeWithStickgif.gif
 
ADVERTISEMENT
ADVERTISEMENT