BS: Hurricanes & Earthquakes - related?

Subject: BS: Hurricanes & Earthquakes - related?
From: Mr Red
Date: 21 Sep 17 - 06:00 AM

Yes yes, Mexico City is prone to earthquakes. Hence this question.

But I was wondering, with all that storm surge pulling water into the gulf adding weight to the Earth's crust locally then releasing it, it must be giving the crust a kick (in geological timescales). And several kicks this year.
Look at how glass behaves - it is a super-cooled liquid after all (no latent heat of fusion). If it has a crack/scratch and you tap it - it splits/lengthens. cf the crust.

FWIW
The Gulf of Mexico has a mean sea level 6ft above the Pacific side of the isthmus. Due to tidal drag.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 21 Sep 17 - 06:09 AM

Mr Red. A qualified yes. The same as filling large reservoirs or injection(eg fracking) can create microseismic events, as also can pumping from oil and gas reservoirs.

http://www.nature.com/nature/journal/v459/n7248/full/nature08042.html?foxtrotcallback=true


https://sites.ualberta.ca/~vanderba/papers/DKV09.pdf

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Teribus
Date: 21 Sep 17 - 06:20 AM

I thought that the tidal surge you get from large tropical storms are caused by high but very localised pressure difference and wind speed pushing, acting on, the water that was already there, I don't think that any additional water has been pulled in from anywhere.

Seen and experienced the effects of two hurricanes close up while at sea on an RN ship acting as "Hurricane Guard Ship" out in the West Indies. This Hurricane season seems to be a very active one with fierce Hurricanes sweeping in one after another which makes relief and emergency work extremely difficult.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Keith A of Hertford
Date: 21 Sep 17 - 06:28 AM

No link has ever been found between tides and quakes, so it seems unlikely.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Nigel Parsons
Date: 21 Sep 17 - 06:39 AM

Although no link has been found yet, we are seeing new extremes of weather, and are better placed to link cause and effect than we have previously been.
I wouldn't rule out there being a causal link.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 21 Sep 17 - 07:03 AM

K of H. FYI Proceedings of the National Academy of Sciences


https://www.livescience.com/55448-how-tides-trigger-san-andreas-earthquakes.html

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Jim Martin
Date: 21 Sep 17 - 07:07 AM

The thing I can't get my head around is that the earthquake occured to the day 35 yrs ago when one occured & when earthquake drill was taking place somewhere!

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: David Carter (UK)
Date: 21 Sep 17 - 07:09 AM

Tides are caused by the difference in gravitational potential of the moon and the sun on opposite sides of the earth. Tidal forces do act on other bits of the earth than water, but this hasn't changed significantly for hundreds of millions of years. Earthquakes are caused by motions of tectonic plates, and the largest ones are subduction earthquakes where one plate is thrust below another.

Teribus and Keith are right, there is no link between tides and quakes, and the storm surge caused by a hurricane (which is not a tide, though it has the same effect) will have no effect on the motions of tectonic plates.

Microseismic events maybe, but not of any significant magnitude and not at any significant depth. The point about fracking is that material is pumped at high pressure deep underground.

What Liu, Linde and Sacks call "slow earthquakes" are movements of plates which occur over long periods of time, and are not destructive

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 21 Sep 17 - 07:29 AM

Sorry David Carter you are incorrect. The entire crust is stressed and requires varying amounts of additional imposed stress to create failure and hence earthquakes. Look at any geological map and it is smothered in faults. Each one has created earthquakes when movement has occurred and retains that capability to an extent dependent upon numerous factors. Suffice it to say that in some areas a very slight increases in stress create minor earthquakes. In other areas far greater additional stresses are required to cause failure, thereby creating earthquakes of far greater severity.
Simplistically any area of the earth is an accident waiting to happen.
Frequency and severity of earthquakes is a function of multiple factors including the stress regime where the earthquake occurs.
Daily tide stresses were previously thought to be insufficient, recently, however, they have been found to correlate significantly with small earthquakes, just before large earthquakes occur.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 21 Sep 17 - 07:54 AM

" Earthquakes are caused by motions of tectonic plates, and the largest ones are subduction earthquakes where one plate is thrust below another."
No plate margin near UK yet quakes in last 50 days below.
http://www.crondallweather.co.uk/earthquake.html#.WcOn5saX3IU

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: David Carter (UK)
Date: 21 Sep 17 - 09:43 AM

Without wanting to come over all Paul Hogan here, those aren't earthquakes. The strongest of those was 4 on the Richter scale. An increase of 1 on the Richter scale corresponds to an increase in energy released of a factor 31.6. The recent Mexico city earthquake was 7.1, so energy released a factor 45000 greater than the strongest of those UK events. I am not sure whether thats a subduction earthquake. Sumatra 2004 and Tohoku 2011 which were subduction events were 9.1 on the Richter scale, which according to my calculator app releases 44.5 million times as much energy as the very strongest of those UK events.

Now you do get moderately strong earthquakes away from subduction zones, famously the New Madrid earthquakes in the central USA in the early 19th century. The San Andreas fault is a lateral fault so the plates are sliding laterally past each other (rather than one under the other as in a subduction zone). This type of fault likewise gives rise to moderately strong earthquakes.

The recent Mexico city earthquake seems to have triggered an eruption of Popocatepetl. Some people were briefly concerned about the proximity of the 2004 Sumatra earthquake to Toba Lake. And you really, really don't want an eruption of Toba lake.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Mr Red
Date: 21 Sep 17 - 10:13 AM

no link between tides and quakes

A very definite and sweeping statement about a "science" that most geologists (like my bro-in-law) will tell you is an art. Predicting earthquakes that is.

In these contexts I invariably point to friction and notably stiction. If you want an old mechanical instrument to overcome that last bit of uncertainty what do you do? Lets take the familiar barometer. Do you tap it gently and see if there is any minor change? Or on lathes add vibration, commercially? Even with lubrication abounding.

Now could we look at a fault line? And by magnification compare it to two metal surfaces rubbing against each other. Those surfaces look similar to the imagined fault line (which can be 50 miles wide). So a low pressure area lifts the water, and after it has gone the water rocks in a second order oscillation decaying exponentially in amplitude. An effect well seen in Lake Michigan because of the shape thereof. Timescales are days and weeks.

Hence that tap tap from about three major hurricanes. And an earthquake waiting to happen. All it needs is to exceed the current threshold.

And isn't one proposed solution (on the San Andreas) to large quakes to pump water into the fault line to lubricate it? Thus causing more frequent and less devastating ones.

Not proof, but a reasoned scenario cf sweeping NO.

ever sat as a weather front arrives? I have and on my timescale - relatively modest though it may be it goes "BANG"!

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Steve Shaw
Date: 21 Sep 17 - 10:14 AM

It's an idea which can't be dismissed out of hand, but in general we know what causes major earthquakes in the particular places they occur. Localised water pile-ups are generally sea surface-only phenomena (unlike tsunamis) caused by wind or changes in air pressure. The energy generated in those events in the sea is minuscule compared to that of the long-term build-up and release of stresses that lead to major earthquakes. It's also worth remembering that most major earthquakes happen several, or many, kilometres below the actual epicentres, well away from the influence of what might be going on on top.

Phreatic volcanic eruptions are a different matter...

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Stu
Date: 21 Sep 17 - 10:33 AM

I had a skim through and it's a fascinating paper. It's not the storm sure that causes the slow quakes, it's the drop in atmospheric pressure associated with the storm reducing the vertical stress on the crust. Also, not all slow earthquakes are caused by typhoons apparently.


"What Liu, Linde and Sacks call "slow earthquakes" are movements of plates which occur over long periods of time, and are not destructive"

No, they are still earthquakes just a different type of quake; this phrase would have been picked up in peer review (or before almost certainly but the editor). They move immense amounts of crust and play a role in triggering ordinary earthquakes.


"I don't think that any additional water has been pulled in from anywhere."

A storm is not a closed system so exchanges of all sorts will occur between it and the environment it exists in and air, water, heat etc will all move in and out of the storm's vicinity.


Pedant's note: The Richter scale isn't used anymore and hasn't been since the seventies.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 21 Sep 17 - 11:17 AM

Stu. It is an interesting field of study and research tends to indicate that it is subtle changes in atmospheric pressure on pore water that acts as the causative mechanism in some cases.


http://adsabs.harvard.edu/abs/2015AGUFM.S13B2835W
It can be argued that barometric pressure variations may cause thresholds to be exceeded and trigger minor earthquakes or even initiate major earthquakes. It is also argued that the massive rainfall during typhoons/hurricanes can trigger landslips thereby altering the quasi equilibium of the crust leading to a time delayed earthquake as equilibrium is sort. It is an active field of research and slowly changing many long held views.

http://www.newsweek.com/hurrica

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Donuel
Date: 21 Sep 17 - 12:20 PM

Earthquakes will not be forever although we can trigger earthquakes by injecting water deep underground acting like a lubricant between rock layers. This was proven 57 years ago when the Air Force injected water and nerve gas deep beneath Colorado Springs.

As long as tectonic plates float on top of liquid rock they will run into one another producing earth quakes. If a fraction of a percent increase or decrease of gravity triggers an earthquake so be it but this is still a planet of geologic motion that will produce earthquakes should the molten core freeze before the red giant sun approaches the Earth. The final earth quake will be the Earth tearing apart as it descends into the sun.

While earthquakes may occur anywhere the frequency of earthquakes around the ring of fire in the Pacific is a remnant of the disruption caused by a massive impact that surprisingly created our moon.
It is also the reason the upwelling of the heaviest metals like gold are also found surrounding that great circle..

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Donuel
Date: 21 Sep 17 - 12:26 PM

edit

"this is still a planet of geologic motion that will produce earthquakes UNTIL the molten core freezes before the red giant sun approaches the Earth. The final earth quake will be the Earth tearing apart as it descends into the sun." if the core freezes by then.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Keith A of Hertford
Date: 21 Sep 17 - 12:27 PM

Studies have been done to search for correlations, but none have been found.
The research quoted by Ians referred only to very deep and very minor (less than 1 on Richter) tremors, not what anyone would call an earthquake.

No link has ever been established between actual earthquakes and the local state of the tide, maritime or geo.

It is hard to see how such a link could have been missed.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Nigel Parsons
Date: 21 Sep 17 - 12:29 PM

The original question was about Hurricanes & earthquakes

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Donuel
Date: 21 Sep 17 - 12:41 PM

In our universe all things are related at some level but not at a significant causal relationship.

I used to think religion was related to an anticipated nuclear war/
Now I relate a secular and ignorant Trump to a nuclear war.

Actually nuclear weapons are most related to nuclear war.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Teribus
Date: 21 Sep 17 - 12:58 PM

It was more the idea of a tropical storm, in this case a hurricane dragging water in from the Atlantic into the Gulf of Mexico or into the Caribbean seem rather bizarre.

Two large storms that caused massive flooding in areas where the low pressure stem driving the storm did not more in the predicted direction and the storms coincided with a period of High Astronomical Spring Tide. The two storms were:

1: On the night of Saturday, 31 January 1953 in the North Sea caused major flooding in the Netherlands, Belgium, England and Scotland. The Low as it passed over the UK pushed water northwards in the North Sea, then instead of tracking North East as these storms normally do it tracked directly East and as the storm made the European mainland the mass of water held to the North of the North Sea the storm wind swept them southwards to coincide with the HAST.

2: 1970 Bhola Cyclone a devastating tropical cyclone that struck East Pakistan and India's West Bengal on November 12, 1970. It remains the deadliest tropical cyclone ever recorded and one of the deadliest natural disasters. Up to 500,000 people lost their lives in the storm, primarily as a result of the storm surge that flooded much of the low-lying islands of the Ganges Delta.

In both cases it was the water already in the North Sea and in the Bay of Bengal that did the damage - no water was dragged from anywhere else.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 21 Sep 17 - 01:10 PM

Eathquakes, temblors, tremblors are all the same thing. The unit of measurement is the moment magnitude(similar to richter for intermediate values-more accurate for higher values)
As I said previously research is ongoing, and instrumentation is   becoming more sensitive, as is computing power and analysis. %0 years ago the analysis carried out today would have been merely a dream, with each passing decade more and more is possible(egSchlumberger cutting edge techniques and instrumentation)
A lot of the relevant science is in it's infancy. I think some real progress is very close. Part of the problem is that today science is divided into increasingly specialised compartments. In reality there is no such beast as a geologist anymore, the field is too wide.
While we know much about seismology, rock mechanics and soil mechanics and meteorology, cross fertilisation between the disciplines is too much of a rarity. The thread under discussion highlights the problem admirably.

https://www.earthmagazine.org/article/blame-it-rain-proposed-links-between-severe-storms-and-earthquakes

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Keith A of Hertford
Date: 21 Sep 17 - 01:39 PM

Changes in air pressure over the sea are not transferred to the sea bed. Water is drawn in to compensate for a reduction, and vice versa.
Over land, hurricanes rapidly weaken.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Stu
Date: 21 Sep 17 - 02:22 PM

"As long as tectonic plates float on top of liquid rock"

The plates don't float on molten rock, rather the rock underneath (the mantle) exhibits plasticity and it's the convection of this ductile rock that drives plate movement.


"no water was dragged from anywhere else."

Like I say, it's not a closed system and all the water in all the seas interact. Sea water is dragged around the worlds oceans by currents.


"Changes in air pressure over the sea are not transferred to the sea bed."

Wrong. High pressure systems depress sea levels and change the density of seawater, which is compressible. This pressure will be transferred to the seabed as the sit sits open top of that.

Everything is interconnected. Everything affects everything else. As I said earlier, these are NOT closed systems and interact with their surroundings. It is that simple.


"Over land, hurricanes rapidly weaken."

Er, yup.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 21 Sep 17 - 02:42 PM

Salinity and temperature affect density, Pressure on the seabed is a function of density and depth. Depth is modified by meteorological effects as mentioned, and these are amplified in enclosed areas.
NOAA "Local wind and weather patterns also can affect tides. Strong offshore winds can move water away from coastlines, exaggerating low tide exposures. Onshore winds may act to pile up water onto the shoreline, virtually eliminating low tide exposures. High-pressure systems can depress sea levels, leading to clear sunny days with exceptionally low tides. Conversely, low-pressure systems that contribute to cloudy, rainy conditions typically are associated with tides than are much higher than predicted."

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Steve Shaw
Date: 21 Sep 17 - 02:47 PM

You tell 'em, Stu. In the end, real science will always win out. 👍🏼

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: David Carter (UK)
Date: 21 Sep 17 - 03:38 PM

The effect of pressure upon the density of seawater is really, really small. There is a calculator here.

So I am not convinced that a significant fraction of an atmospheric pressure change is transferred to the seabed.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Donuel
Date: 21 Sep 17 - 03:48 PM

Core, mantle or crust, its all rock in flux to me.

Some claim radioactive elements keep the core hot more than gravitational pressure.

Stu do you have a degree in Physics, geology, chemistry ?

Of course a PhD is a bit more reliable but not mandatory, except for employers. I love Earth science. We can practically touch it.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 21 Sep 17 - 04:22 PM

For seabed pressure you need to calculate the hydrostatic head of seawater. This runs .433 to .435psi/ft depending on temp and salinity.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Nigel Parsons
Date: 21 Sep 17 - 05:00 PM

From: Iains - PM
Date: 21 Sep 17 - 04:22 PM

For seabed pressure you need to calculate the hydrostatic head of seawater.

Surely that should be "plus the atmospheric pressure immediately above the seawater"

I only went as far as A-level physics, but I can still spot obvious errors in statements.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Steve Shaw
Date: 21 Sep 17 - 06:44 PM

Well seabed pressure(?)/hydrostatic pressure/atmospheric pressure have always been with us. In the overall scheme of things, any effect of variations in them that might impact on the earth's crust, in which severe earthquakes usually happen at great depths, is minuscule. So the null hypothesis is that, as there is no evidence for those phenomena being causes for major earthquakes, they have little or no effect on seismic phenomena. Science can go no further without your evidence to the contrary. You have precious little such evidence, and just a reminder that speculation and flights of the imagination are not evidence.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Nigel Parsons
Date: 21 Sep 17 - 07:37 PM

From: Steve Shaw - PM
Date: 21 Sep 17 - 06:44 PM

Well seabed pressure(?)/hydrostatic pressure/atmospheric pressure have always been with us. In the overall scheme of things, any effect of variations in them that might impact on the earth's crust, in which severe earthquakes usually happen at great depths, is minuscule. So the null hypothesis is that, as there is no evidence for those phenomena being causes for major earthquakes, they have little or no effect on seismic phenomena. Science can go no further without your evidence to the contrary. You have precious little such evidence, and just a reminder that speculation and flights of the imagination are not evidence.

And I thought that you insisted that the Scientific method didn't deal with proofs.

This thread seems to put forward a theory, which, in the absence of any evidence against it, should be allowed to stand as a theory.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Mr Red
Date: 22 Sep 17 - 03:52 AM

As theories go - would anyone care to compare my posit with one that has the hurricanes and the suffering, and an earthquake in the vicinity - a direct result of God (whoever she is) punishing us for electing Trump?

And............... on the Wreckter scale, which will prove more devastating?

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 22 Sep 17 - 03:53 AM

" they have little or no effect on seismic phenomena"


From the National Oceanic and Atmospheric Administration.""Local wind and weather patterns also can affect tides. Strong offshore winds can move water away from coastlines, exaggerating low tide exposures. Onshore winds may act to pile up water onto the shoreline, virtually eliminating low tide exposures. High-pressure systems can depress sea levels, leading to clear sunny days with exceptionally low tides. Conversely, low-pressure systems that contribute to cloudy, rainy conditions typically are associated with tides than are much higher than predicted."
1)Therefore high pressure and low pressure systems modify the hydrostatic head of a column of seawater.
2)Low pressure can generate intense storms containing abundant energy leading to exaggerated tides,surges and wave action.
3)All these activities generate seismic noise
4)if the magnitude of the noise due to the above exceeds the failure point of adjacent stressed rocks failure will occur.
5)The failure may be seen as microseismic events or could be larger. This would depend on the nature of the system and the forces acting on it

Rock stress
http://dc-app3-14.gfz-potsdam.de/pub/guidelines/WSM_analysis_guideline_breakout_image.pdf
microseismic events
http://onlinelibrary.wiley.com/doi/10.1029/JB073i012p03945/full
Seismic noise
http://onlinelibrary.wiley.com/doi/10.1029/2007GC001814/pdf

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Keith A of Hertford
Date: 22 Sep 17 - 04:14 AM

Stu,
Even if sea water density was significantly changed by pressure, which it is not, changes in atmospheric pressure are not transferred to the sea bed.
A fall in air pressure produces a sea level rise to compensate.
A barometric rise causes a sea level depression to compensate.
You can not have adjacent areas of sea bed with different hydrostatic pressures without creating a flow of water to even them out.

You tell 'em, Stu. In the end, real science will always win out.

He got it wrong Steve.

Wind however can produce such effects because the compensating flows are slower.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 22 Sep 17 - 04:57 AM

I am sure some will still want to argue!

meteorological triggering of earthquakes

rain triggered earthquakes
Haiti earthquake perhaps triggered by storm erosion


possible tidal correlation with earthquake swarms

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Steve Shaw
Date: 22 Sep 17 - 05:08 AM

Mr Red's longer post contains the kind of reasoning that amounts to a hypothesis. The next step would be to gather evidence. The kind of speculations raised in this thread are neither evidence nor theories, though they may form a basis for seeking evidence. That's as far as it goes. Interested parties, off you go to find evidence. And Nigel, I didn't mention proof. I don't know where that's supposed to have come from.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Stu
Date: 22 Sep 17 - 06:04 AM

"Stu do you have a degree in Physics, geology, chemistry ?"

No, I was doing a part-time self-funded PhD in vertebrate palaeontology until this time last year, when I was forced to withdraw after three years because my senior supervisor 'left' and no suitable replacement was found, and it turned out the specimen I was working on wasn't owned by my institution but was still partially in private hands and so I had to stop working on it. This put the kibosh on the whole endeavour and I was out. Appalling mess. I had just finished gaterhing the data on this specimen too, so that was three years pissed away.

Although I go my fees back, I spent at least as much again on travel, equipment etc and I couldn't budget for another seven years of research, so I'm hoping to do an MPhil and see how I go on from there.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Keith A of Hertford
Date: 22 Sep 17 - 06:05 AM

From Ians' final link.
" The statistical test however did not prove a statistically significant correlation indicating a triggering effect of fault extension due to tidal loading. We also examined tidal effects to the already running seismic activity of the prominent 2000 swarm by comparing the tidal stress distribution in the investigated period with the distribution of tidal stresses in the occurrence times of each earthquake. The results show that these distributions are almost similar, which indicates that individual earthquakes occur independent of tidal stresses."

No correlation has been found between actual earthquakes and tides either, though there have been a number of studies that looked for them.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Stu
Date: 22 Sep 17 - 06:36 AM

"Even if sea water density was significantly changed by pressure, which it is not, changes in atmospheric pressure are not transferred to the sea bed."

High pressure systems alter the density of the water throughout the water column, and this will of course affect pressure at the seabed. This an indisputable, observable fact.

The issue here is we're veering towards the usual Mudcat reductionism, and in this case that really means the argument is worthless. There is an effect of atmospheric pressure on the density of seawater, but it's part of a very complex system with literally millions of variables. What this means for plate tectonics I have no idea.

However, as the paper first link in Iain's original post makes clear, atmospheric pressure seems to affect seismicity and trigger slow earthquakes (and other events?). Does this happen at plate boundaries? I don't know, but it's not an unreasonable hypothesis to suggest it does.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Keith A of Hertford
Date: 22 Sep 17 - 09:05 AM

High pressure systems alter the density of the water throughout the water column, and this will of course affect pressure at the seabed. This an indisputable, observable fact.

No, it is rubbish.
There is no significant change in density due to air pressure. The entire pressure of the whole atmosphere is equivalent to about 10m of water. Changes in pressure only centimetres.
Even a full 10m does not compress water!

Even if it did, air pressure changes would still not be transferred to the sea bed.
The actual effect of changes in air pressure is to raise or lower the sea level, which negates any pressure change at the sea bed, or at any given depth.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Steve Shaw
Date: 22 Sep 17 - 09:15 AM

We were told at school that one property of liquid water is that it is virtually incompressible.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Stu
Date: 22 Sep 17 - 09:18 AM

This discussion has given me invaluable insight into the way you structure and support your arguments Keith. Unlike many here I've always given you the benefit of the doubt.


"The entire pressure of the whole atmosphere is equivalent to about 10m of water."

This statement is utterly meaningless. I'm not arguing with you when your arguments are based on personal incredulity etc.

However, Keith's attitude does raise an interesting point, and one scientists wrestle with constantly. How do we communicate our science to people in a way they can understand? As a dinosaur worker this is made easier for me as everyone is interested in dinosaurs, but the sort of research published in Iain's original link whilst fascinating and quite wonderful is much harder to communicate in a way that helps people relate the research to their own lives.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Stu
Date: 22 Sep 17 - 09:49 AM

"We were told at school that one property of liquid water is that it is virtually incompressible."

At a constant temperature and pressure.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Keith A of Hertford
Date: 22 Sep 17 - 11:25 AM

"The entire pressure of the whole atmosphere is equivalent to about 10m of water."
This statement is utterly meaningless.

No, it is correct. Do you not understand?
The pressure of the atmosphere at the Earth's surface is equivalent to the pressure under 10m of water (or 76cms mercury.)

"We were told at school that one property of liquid water is that it is virtually incompressible."
Correct Steve.
At a constant temperature and pressure.

No Stu. Pressure has no effect on its volume.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Keith A of Hertford
Date: 22 Sep 17 - 11:27 AM

Stu,
"The entire pressure of the whole atmosphere is equivalent to about 10m of water."
This statement is utterly meaningless.

No, it is correct. Do you not understand?
The pressure of the atmosphere at the Earth's surface is equivalent to the pressure under 10m of water (or 76cms mercury.)

"We were told at school that one property of liquid water is that it is virtually incompressible."
Correct Steve.

At a constant temperature and pressure.
No Stu. Pressure has no effect on its volume.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Stu
Date: 22 Sep 17 - 11:43 AM

http://pubs.acs.org/doi/abs/10.1021/jp0136260

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Teribus
Date: 22 Sep 17 - 12:06 PM

High Pressure Systems?

"A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, and simply cyclone. A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean, and a cyclone occurs in the south Pacific or Indian Ocean."

Anti-cyclones are storms caused by High Pressure Systems and are restricted to the bands of latitude North and South of the Equator known as "The Horse Latitudes" (Between 30 and 38 degrees North and South of the Equator).

"An anticyclone (that is, opposite to a cyclone) is a weather phenomenon defined by the United States National Weather Service's glossary as "a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere, counterclockwise in the Southern Hemisphere". Effects of surface-based anticyclones include clearing skies as well as cooler, drier air. Fog can also form overnight within a region of higher pressure."

Only time I have had to deal with water under pressure has been connected with the hydrostatic testing of pipelines and pressure vessels. All water contains minute quantities of air in solution. In conducting a hydrostatic test of a pressure vessel or a pipeline pressure is built up gradually to the point at which this included gas is forced out of solution. At this point a hold is made, and an air inclusion test is performed. The pressure drops slightly during this hold and the extent of the drop is noted along with the temperature both at the surface and on the seabed if you are testing a pipeline. Having acquired the pressure drop due to included air the vessel or pipeline is then cycled up to full test pressure - On achieving that everything apart from the instrumentation lines are locked off and sealed and pen recorders graphically measure temperature, pressure and time. The Test is conducted over a 24 hour period. The pressure in the vessel or pipeline is allowed to fluctuate within given parameters that can be fully explained due to included air, and temperature variations - atmospheric pressure is not considered as the system under test is isolated. A steady pressure hold within those explainable parameters indicates a successful test, an unaccountable steady drop indicates a leak.

The influence of atmospheric pressure on the density of sea water and on the seabed would I think be so miniscule to be completely insignificant.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Steve Shaw
Date: 22 Sep 17 - 01:05 PM

Well I agree with that last statement.

An anticyclone isn't a storm. In an anticyclone the air is descending, which increases its pressure which warms it. Typically, a temperature inversion forms which prevents air rising. An anticyclone that is completely self-contained, with no influence from advected air, will tend to warm up in summer as insolation and the warming effect of the descending air outdoes heat loss from the ground by radiation (the sun is higher, therefore stronger, and shines for more hours). The opposite happens in winter, so large anticyclones, especially the ones over landmasses, can get very cold, such as the one that forms over Siberia in winter.

Happy equinox, world.

Subject: RE: BS: Hurricanes & Earthquakes - related?
From: Iains
Date: 22 Sep 17 - 02:04 PM

"but the sort of research published in Iain's original link whilst fascinating and quite wonderful is much harder to communicate in a way that helps people relate the research to their own lives"

How right you are.
Hydrostatic head of fresh water is 0.433psi/ft
minimum atmospheric pressure measured 870mb=12.62psi/ft
Maximum atmospheric pressure 1083mb=15.71psi/ft
The difference is 3.09psi=7.1ft as a water column
Therefore the difference between minimum low pressure and maximum high pressure is equivalent to a maximum change in hydrostatic of seawater of 7.1psi BUT low pressure diminishes sea level high pressure increases it. Note I only used fresh water andhave not introduced temperature. Looking at the numerous bars on ship's plimsoll line gives an indication of how the story can complicate.
I hope this clarifies the issue. Having spent years doing these calculations on a daily basis I tend to take the concepts for granted.I do not offer it as an excuse if I have given a poor explanation though


I hope