Earth Quake statistics & Locations

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We had another 4.3 last night. It woke me up. We’ve been having a lot of earthquakes lately and they’re lasting longer. I bought earthquake insurance just in case. I thought that a bunch of little ones would release the pressure and prevent larger ones, but I guess that’s a myth, eh? Is it true, though, that bigger earthquakes can be triggered by smaller ones? Undecided
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(Apr 29, 2019 04:12 PM)Secular Sanity Wrote: We had another 4.3 last night. It woke me up. We’ve been having a lot of earthquakes lately and they’re lasting longer. I bought earthquake insurance just in case. I thought that a bunch of little ones would release the pressure and prevent larger ones, but I guess that’s a myth, eh? Is it true, though, that bigger earthquakes can be triggered by smaller ones? Undecided


In the "slow-slip" theory, foreshocks are treated as indicators of gradual rupturing in the same region of a fault which could eventually lead to a large earthquake. But in terms of predictions, its problem is distinguishing those so-called "special" foreshocks from ordinary minor quakes.

In the cascade model, foreshocks can be regarded as moving along a fault by each starting another nearby until the series triggers a dramatic earthquake. Half of those cascading sequences fizzle out, however, so they're not even entertained as reliable forecasts of big ones.
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M 6.2 - Carlsberg Ridge
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Time 2019-04-29 14:19:52 (UTC)
Location 10.882°N 57.239°E
Depth 10.0 km

(Apr 29, 2019 04:12 PM)Secular Sanity Wrote: We had another 4.3 last night. It woke me up. We’ve been having a lot of earthquakes lately and they’re lasting longer. I bought earthquake insurance just in case. I thought that a bunch of little ones would release the pressure and prevent larger ones, but I guess that’s a myth, eh? Is it true, though, that bigger earthquakes can be triggered by smaller ones?  Undecided


M 4.3 - 10km NNW of Redwood Valley, CA
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[Image: tsunami.jpg]

Time 2019-04-29 07:16:08 (UTC)
Location 39.348°N 123.235°W
Depth 3.1 km

the depth of this one and the probable direction of movement would make it a lot more noticeable than most others of a similar size.

with populations more spread you have more people occupying more of the land
with systems that rely on no serious movement to maintain systems, movement becomes more of an issue.

e.g 200 years ago an entire village could be wiped out by an earth quake and no one would have known or noticed.
500 years ago, an entire city could be wiped out by an earth quake and no one(globally) would know.


CC answers your question scientifically.
what is not included is the issues that scare people and make good panic headlines like the big faults

"slow slips"
"thrusts"
"mega thrusts"
"subductions"

there are many names for different types of movement depending on what causes it.

basically the plates are always moving
generically over a long time period there is a certain amount of movement that gets forced.
generally that means earth quakes of a certain size roughly on a regular time basis(over several hundred years or decades or thousands of years)
this is all historical data based on probability of the old pattern continuing roughly along a similar pattern.


i have been attempting to note patterns prior to larger quakes for the last 10 years.
no recorded data
all just mentally in my memory
i have noticed what seems to be some patterns of movement, however.
none of those patterns seem to be a clear indicator of any ability to predict a larger quake with any accuracy above a 60% rough guide.


based on my current understanding and models i can gues a probable most likely quake position based on various other quakes.
however, the actual occurance of those quakes is not much more than around 50/50 which makes it fairly useless.


there is a general flow pattern of quakes but there seems to be no obvious way to judge the continuation of the sequence of events as CC noted.
except with some rough general indicators of size & location and depth.
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(Apr 29, 2019 08:53 PM)C C Wrote: In the "slow-slip" theory, foreshocks are treated as indicators of gradual rupturing in the same region of a fault which could eventually lead to a large earthquake. But in terms of predictions, its problem is distinguishing those so-called "special" foreshocks from ordinary minor quakes.  

In the cascade model, foreshocks can be regarded as moving along a fault by each starting another nearby until the series triggers a dramatic earthquake. Half of those cascading sequences fizzle out, however, so they're not even entertained as reliable forecasts of big ones.

(Apr 30, 2019 12:22 AM)RainbowUnicorn Wrote: based on my current understanding and models i can guess a probable most likely quake position based on various other quakes.
however, the actual occurrence of those quakes is not much more than around 50/50 which makes it fairly useless.


there is a general flow pattern of quakes but there seems to be no obvious way to judge the continuation of the sequence of events as CC noted.
except with some rough general indicators of size & location and depth.

Well, that at least gives me a little more peace of mind. Adding double sided sticky tape to my shopping list.

Thanks to the both of you!
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M 5.6 - 44km ESE of Miyazaki-shi, Japan
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Time 2019-05-09 22:43:24 (UTC)
Location 31.809°N 131.873°E
Depth 35.0 km

M 6.1 - 43km ESE of Miyazaki-shi, Japan
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Time 2019-05-09 23:48:42 (UTC)
Location 31.782°N 131.854°E
Depth 23.0 km

M 5.1 - 41km ENE of Nichinan, Japan
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Time 2019-05-10 00:07:38 (UTC)
Location 31.683°N 131.793°E
Depth 35.0 km

M 4.6 - 45km ESE of Nichinan, Japan
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Time 2019-05-10 04:53:47 (UTC)
Location 31.396°N 131.786°E
Depth 10.0 km
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