Undersea earthquakes shake up climate science

CALIFORNIA INSTITUTE OF TECHNOLOGY

Research News

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IMAGE: AN ARTIST’S RENDERING OF UNDERSEA EARTHQUAKE WAVES. view more CREDIT: CALTECH

Despite climate change being most obvious to people as unseasonably warm winter days or melting glaciers, as much as 95 percent of the extra heat trapped on Earth by greenhouse gases is held in the world’s oceans. For that reason, monitoring the temperature of ocean waters has been a priority for climate scientists, and now Caltech researchers have discovered that seismic rumblings on the seafloor can provide them with another tool for doing that.

In a new paper publishing in Science, the researchers show how they are able to make use of existing seismic monitoring equipment, as well as historic seismic data, to determine how much the temperature of the earth’s oceans has changed and continues changing, even at depths that are normally out of the reach of conventional tools.

They do this by listening for the sounds from the many earthquakes that regularly occur under the ocean, says Jörn Callies, assistant professor of environmental science and engineering at Caltech and study co-author. Callies says these earthquake sounds are powerful and travel long distances through the ocean without significantly weakening, which makes them easy to monitor.

Wenbo Wu, postdoctoral scholar in geophysics and lead author of the paper, explains that when an earthquake happens under the ocean, most of its energy travels through the earth, but a portion of that energy is transmitted into the water as sound. These sound waves propagate outward from the quake’s epicenter just like seismic waves that travel through the ground, but the sound waves move at a much slower speed. As a result, ground waves will arrive at a seismic monitoring station first, followed by the sound waves, which will appear as a secondary signal of the same event. The effect is roughly similar to how you can often see the flash from lightning seconds before you hear its thunder.

“These sound waves in the ocean can be clearly recorded by seismometers at a much longer distance than thunder — from thousands of kilometers away,” Wu says. “Interestingly, they are even ‘louder’ than the vibrations traveling deep in the solid Earth, which are more widely used by seismologists.”

The speed of sound in water increases as the water’s temperature rises, so, the team realized, the length of time it takes a sound to travel a given distance in the ocean can be used to deduce the water’s temperature.

“The key is that we use repeating earthquakes–earthquakes that happen again and again in the same place,” he says. “In this example we’re looking at earthquakes that occur off Sumatra in Indonesia, and we measure when they arrive in the central Indian ocean. It takes about a half hour for them to travel that distance, with water temperature causing about one-tenth-of-a second difference. It’s a very small fractional change, but we can measure it.”

Wu adds that because they are using a seismometer that has been in the same location in the central Indian Ocean since 2004, they can look back at the data it collected each time an earthquake occurred in Sumatra, for example, and thus determine the temperature of the ocean at that same time.

“We are using small earthquakes that are too small to cause any damage or even be felt by humans at all,” Wu says. “But the seismometer can detect them from great distances , thus allowing us to monitor large-scale ocean temperature changes on a particular path in one measurement.”

Callies says the data they have analyzed confirm that the Indian Ocean has been warming, as other data collected through other methods have indicated, but that it might be warming even faster than previously estimated.

“The ocean plays a key role in the rate that the climate is changing,” he says. “The ocean is the main reservoir of energy in the climate system, and the deep ocean in particular is important to monitor. One advantage of our method is that the sound waves sample depths below 2,000 meters, where there are very few conventional measurements.”

Depending on which set of previous data they compare their results to, ocean warming appears to be as much as 69 percent greater than had been believed. However, Callies cautions against drawing any immediate conclusions, as more data need to be collected and analyzed.

Because undersea earthquakes happen all over the world, Callies says it should be possible to expand the system he and his fellow researchers developed so that it can monitor water temperatures in all of the oceans. Wu adds that because the technique makes use of existing infrastructure and equipment, it is relatively low-cost.

“We think we can do this in a lot of other regions,” Callies says. “And by doing this, we hope to contribute to the data about how our oceans are warming.”

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The paper describing the research, titled, “Seismic Ocean Thermometry,” appears in the September 18 issue of Science. Co-authors are Wenbo Wu, postdoctoral scholar in geophysics; Zhongwen Zhan (PhD ’13), assistant professor of geophysics; and Shirui Peng, graduate student in environmental science and engineering, all from Caltech; and Sidao Ni (MS ’98, PhD ’01) of the Institute of Geodesy and Geophysics at the Chinese Academy of Sciences.

From EurekAlert!

96 thoughts on “Undersea earthquakes shake up climate science

  1. This story appeared on a BBC website a couple of days ago. I commented on it on Willis Eschenbach’s excellent site and got an eminent Earth scientist friend of mine (we were once students together) to look into the matter as well. My two emails can be found here: https://rosebyanyothernameblog.wordpress.com/openthread01/comment-page-5/#comment-15220
    The take-away line comes from my Earth scientist peer:
    “To summarise I think that the probability that changes in deep ocean temperatures over the last few decades can be measured with confidence by comparing earthquake arrival times is almost vanishingly small. I would have loved to have been a referee on the paper which gave rise to this all too predictable BBC article.”
    QED

    • They’re going to have a hard time factoring in depth….and depth/pressure will make the most difference

      ….and yes, what they are trying to measure is infinitesimally small

        • What about clock synchronicity accuracy.
          I have a clock in my house that loses a second per day compared to three others in my house
          To make a tenth of a second time difference over a period of time can also be a clock problem unless all events are measured by a single clock

      • Not to mention total Doppler shift due to average ocean current occurring over the total acoustic path in the ocean between earthquake source and detector.

        The article asserts they will be measuring the ocean’s acoustic signal to a resolution of 0.1 second out of about 1800 seconds (“half hour”) due to “water temperature causing about one-tenth-of-a second difference”.

        So what would the vector-resolved average magnitude of ocean current speed need to be along path/depth length connecting the earthquake source with detector location so that the 0.1/1800 difference is actually caused by Doppler shift instead of water temperature? Well, the average acoustic speed in seawater is about 1500 m/sec, so (0.1/1800)*1500 m/sec = .083 m/sec = 0.16 knots = 0.19 mph.

        The major circulations in Earth’s oceans: “Horizontal movements are called currents, which range in magnitude from a few centimetres per second to as much as 4 metres (about 13 feet) per second. A characteristic surface speed is about 5 to 50 cm (about 2 to 20 inches) per second.”—source: https://www.britannica.com/science/ocean-current .

        The range of 5 to 50 cm/sec is equivalent to a speed range of about 0.1 to 1 knot, or a factor of about 1 to 10 larger than that needed to create a 0.1 second Doppler shift in the measured signal under the above-stated scenario.

        So, unless the researchers propose locating their seismic monitoring stations at great depths in the oceans (say below 1000 m, where the general circulation currents are significantly less), they will have a SIGNIFICANT amount of “noise” from just ocean currents.

        I’m surprised to see such sloppy work coming out of CalTech.

    • The velocity of propagation of sound in sea water depends density. Density depends on temperature and salinity. Oh well, there’s a confounding variable right there.

      When I was a pup, there were systems like Loran and Decca that measured a ship’s position based on the propagation of radio waves through the atmosphere. The atmosphere does have an effect on radio wave velocity of propagation. Navigators and surveyors did corrections for that. So, using the velocity of sound waves to determine the density of the ocean doesn’t sound out of line to me. It’s like something we’ve been routinely doing for a long time.

      On the other hand, there are those confounding variables. It’s not quite as bad as using tree rings as thermometers but …

      My usual reaction is, ‘What am I missing?’ In this case it’s, “What are those guys missing?”

      • In the 70s I was employed with a marine seismic survey company that used Shoran (and similar systems) as a navigation tool for dynamically locating survey ships as they undertook grid surveys offshore. Atmospheric propagation properties could easily change often depending on time of day weather and local flora – tropical forests sucked the hell out of signals! So I’m sure, while this method in principle is sound, there are too many unmeasurable variables. One being how can they be sure that an earthquake occurring in the same location several times over a period is actually has the exact same focus as it’s previous iterations. I would doubt that after the strata have settled after one earthquake the next pressure/fracture point is unlikely to be in the same spot. Then you have the intervening ocean environment: changes in salinity, depth, pressure, temperature, flora and fauna. Not a happy recipe for success.

        • I get the same results by walking around my lit house with my eyes closed pretending I can see. The best one can do is not walk into a wall. Wow.

        • Properly used by clueful hydrographers, systems similar to Shoran (Motorola Mini Ranger (if I recall correctly)) gave accuracy within tenish meters, close enough for sonar work. Another system, Tellurometer, which operated on a different principle was capable of 10 cm accuracy.

      • Don’t forget those dissolved solids either.

        I love how these guys take complex phenomena and boil it down to a single variable.

        Kinda like those dendrochronologists.

        Maybe a new discipline: seismohydropyrologists

      • Commiebob – velocity of propagation of sound in sea water depends on temperature, salinity AND pressure – pressure being controlled by temp and salinity of water column above.

  2. In a thirty second wave travel time they record a one-tenth second difference? That’s 0.3% difference. And the difference is due exclusively to the difference in ocean water temperature? Salinity? Ocean currents? Calibration of the instruments which were never intended for this purpose? I’m more than a little suspicous that this is a bid for more funding.

    • Hey it shows it’s worse that we thought, so it must right !

      “as much as 95 percent of the extra heat trapped on Earth by greenhouse gases is held in the world’s oceans.”

      Oh, cool, they’ve found Trenberth’s “missing heat”. 95%, isn’t that the same as the missing mass in the universe? It’s worse that we thought.

      “…. appears to be as much as …. ” oooh, interesting, interesting.

      “Callies cautions against drawing any immediate conclusions, as more data need to be collected and analyzed.”

      Ah , of course, more work is needed to create you some more “it’s worse than we thought”, do you want buy? I have a basic costing document available.

    • That’s 30 minutes not 30 seconds.

      “It takes about a half hour for them to travel that distance, with water temperature causing about one-tenth-of-a second difference.“

      One-tenth-of-a second difference over 1800 seconds.

    • By my quick calculations, the amount of energy that would increase the average air temperature by 1 degree C would increase the average ocean temperature by 1/13,000th of a degree C. You could hide one heck of a lot of excess atmospheric heat in the oceans without being able to actually measure a change in ocean temperature. Neither air temperature nor ocean water temperature can be sampled and measured accurately enough or to support the claims being made.

      • Air 1 kilojoule per kilogram-K
        Seawater 4 kilojoules per kilogram-K
        So water will be about 1/4 of a K by mass, that is 0.25 K

        Seawater density is about 800 times the same volume of atmosphere at the surface.
        800 times 4 is 3200.
        So for the same volumes, the energy that heats air by 1K will heat seawater by
        1/3200 as much. That equals .0003 Kelvins, or 0.3 millikelvins.

  3. I’ll give them kudos for coming up with this. Unfortunately they are only measuring the average water temperature from source to detector. The water temperature can vary substantially along the way. Some waters may be warmer, some cooler than earlier.

    A lot of undersea earthquakes occur around volcanic activity. If the earthquake occurs because of magma movement which is also heating the water, wouldn’t that skew the results?

    This does give historical data for free, but you kind of wonder just what you get out of it. In this case it just may mean volcanic activity in this particular area has increased.. or something else. Since they are measuring actual data that can be harvested electronically it may be worth going after it. A good doctoral thesis maybe.

    • “Since they are measuring actual data that can be harvested electronically it may be worth going after it. A good doctoral thesis maybe.”

      Yeah, more of start of beginning, rather the end of story. And seems one can measure the entire ocean this way. Or to become accurate enough, it seems one have measure the entire ocean and use other kinds measurements [ie Argo floats} to correct and calibrate it. And eventually, it could improve Argo float measurements.

  4. “The speed of sound in water increases as the water’s temperature rises, so, the team realized, the length of time it takes a sound to travel a given distance in the ocean can be used to deduce the water’s temperature.”

    UM…….what?

    Ok that is a LOT of assumptions there. Most particularly, exactly how far away are they listening and at what depth exactly? The bottom of the ocean is vast and has topography as well as currents, all factors that change how sound travels through water. So what exactly are they measuring here?

    • Speed of Sound is faster through denser water..higher temperature if I am not mistaken is less dense.

      • From the quoted source…
        The water wave velocity change is 4m/s for a one degree temperature change, (centered around 5 C, 1427m/s). I’ll use 5C as an estimate for the deep water temperature profile.

        So if the water temperature had risen 0.16 degrees in the study period, (1C per century), the velocity would have risen from 1427m/s to 1427.7m/s.

        Seismic waves in igneous rock should travel around 7km/s, the actual velocity could be anywhere from 6 to 8km/s even in the same mineral. Change materials and the velocity changes to a higher degree, (eg 3km/s for limestone).

        So for the same mineral and a distance of say 1000km. The time between event and recording could be between 125 and 167 seconds.

        For sound in water, the time of travel would have reduced, (due to 0.16C rise), by 0.34 seconds.

        IF….. you could generate two earthquakes, one in 2004 the other today, at exactly the same location and record the signal time to arrive at exactly the same location, then you could eliminate the material differences, (but not rock temperature). But the earlier earthquake will modify the rock and those fractures alone will change the velocity by an unknown amount.

        Any location change would introduce unknown material changes, in short, material changes due to location changes , even within a single mineral type MAY generate errors that are (40/.34), nearly 120 times larger than the signal intended to be measured.

        Now, where do I get my cash for this 5 minute rebuttal?

    • What are they measuring? Why, their level of commitment to the global warming cause, of course. Without controls over other variables, the data is just noise.

    • US navy has had sonar network as primary way to deter nuclear war and has had for decades. Not sure how much of it, is available for civilian use.
      It seems likely the focus of network is related to global security regions. Also likely Russia and China is also doing this to some degree also in terms separate, whereas other countries would be playing part of this US global security effort to deter nuclear war.

  5. On the face of it an interesting technique. A little thought suggests that the temperature gradient with depth will result in different sound speeds for each thermal layer, smearing the signal. Ocean currents do change over time. So perhaps that is what is being measured here.

    • It doesn’t add up….Yes agree ocean currents do change over time…along with changes in salinity and temperature from sources other than “greenhouse gases”…Just another stupid meaningless metric and a waste of time and money.

      • Other factors affect turbidity of our ocean waters, even seasonal flux.

        This 05 paper discusses turbidity and SSTs;. ”
        Sea Surface Temperature Sensitivity to Water Turbidity from Simulations of the Turbid Black Sea Using HYCOM*

        “In general, the use of spatially and temporally varying turbidity fields is necessary for the Black Sea OGCM studies because there is strong seasonal cycle and large spatial variation in the solar attenuation coefficient, and an additional simulation using a constant kPAR value of 0.19 m−1, the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) space–time mean for the Black Sea, did not yield as accurate SST results as experiments 1 and 4. “

  6. “It takes about a half hour for them to travel that distance, with water temperature causing about one-tenth-of-a second difference.”

    And what would be the error bars?

    • I imagine the uncertainty is magnitudes greater than the temperature difference they claim to have measured.

      When I heard this on BBB a few nights ago I laughed. “Climate science” has become theater of the absurd.

  7. … Caltech researchers have discovered that seismic rumblings on the seafloor can provide them with another tool…

    The results are already written, and the media headline will be:      Worse Than Previously Thought!

  8. Nothing appears to address the question of what’s driving the warming to which they refer. The assumption, one suspects, will be that it’s man-made but where’s the evidence? In fairness Callies is encouraging people to be cautious about drawing conclusions, but that never seems to stop the media doing so.

    Yet another example that will no doubt be used to ‘prove’ man-made global warming when it does nothing of the sort.

    • Hmmm . . . .

      Your point, I believe, lends credence to an alternate hypothesis . . . .

      As has been often observed on WUWT, historically, warming preceds increases in atmospheric CO2 which suggests that atmospheric increases are the result of outgassing disolved CO2 from warming oceans.

      As many here have wondered, very low specific-heat warm air can not add enough heat to warm air high specific-heat water? Well now, if we take this report at face value, maybe it’s not.

      The report asserts that some piece of the Indian Ocean is warming. But that doesn’t settle the chicken-egg dilemma.

      Indeed, if the heat transfer/balance equations can’t account for the increased ocean temperature (it’s worse than we thought), why isn’t as likely that the ocean, warming for reasons that have not yet been determined, is the source of atmospheric CO2.

      In other words, having “determined” that the ocean is warming but being unable to explain how warmer air accounts for the observed oceanic warming, you have to consider . . . maybe it’s not! Further, that oceanic warming could explain increased atmospheric CO2.

      Just wondering . . . .

  9. Confused terminology. A seismometer measures motions of the earth. A sound velocity meter measures the speed of sound. If Mr. Wu is using seismometers in his study, how does he derive the speed of sound in water and the temperature of water from such information?

    Also, Cal Tech said “Despite climate change being most obvious to people as unseasonably warm winter days or melting glaciers…” How is a warm winter day evidence of a changing climate? Is it not evidence of local weather instead? If “people” think that a warm winter day is evidence of climate change, they are seriously ignorant.

    And as Mr. Magness’s friend concluded, one must know the exact location of the origin of repeated sound impulses in water to use a time-of-travel method to measure water temperature changes, and they don’t and most likely cant because the origin of earthquakes normally takes place over broad areas, much larger than required for time-of-travel temperature measurements.

  10. When it comes to the oceans, a FAR bigger concern should be undersea volcanoes and hydrothermal vents. 30 years ago scientists thought there were 10’s of them. A decade later it was hundreds. A decade later thousands. And now they know it’s in the millions. Yet climate models have not changed to cater for this ? An example is what happened early last year – there was a seismic hum heard around the world. No one knew what it was until a few months later they found it was a massive volcano going off deep underwater near Africa. In just 6 months it grew to 5km wide and 1km high. If that had been on land it would have been a supervolcano and would have changed the global climate for years. And these things appear to go off regularly.
    https://www.livescience.com/65545-largest-underwater-volcano-seismic-hum.html
    The then you have the mid ocean ridges, slowly and constantly spewing out lava over thousands of kms. Yet none of the climate scientists think this is important !

  11. The temperature of the deep ocean has nothing to do with average surface temperature. Cold water sinks and as long as there’s any cold water at the poles, the deep ocean beneath the thermocline will remain a constant temperature varying from 0C at the bottom to 4C at the bottom of the thermocline.

    The idea that the entire volume of the ocean must track surface temperatures is completely wrong. Only the top few meters of the solid surface matters and the same is true with the oceans, except that it’s the top few 100 meters.

    The reason is that still water at a sufficient depth becomes a thermal insulator and the thermocline is thick enough and still enough to insulate deep ocean cold from warm surface waters.

    • CO2isnot
      You remarked, “The temperature of the deep ocean has nothing to do with average surface temperature.”
      And yet, the article makes the point that the novelty is that “our method is that the sound waves sample depths below 2,000 meters, …” What they don’t explain is how absorption of solar insolation in surface waters heats deep water.

      Something else that needs explaining is how 95% of the assumed added heat resides in the oceans when the oceans only intercept 70% of the incoming solar rays. Perhaps they are assuming that the difference in reflectivity between land and water allows more insolation to be absorbed over the oceans. However, that doesn’t allow for differences in cloudiness over the two regimes. Further, while the reflectivity of water at solar noon is very low, it can reach 100% on the limbs or terminator.
      https://wattsupwiththat.com/2016/09/12/why-albedo-is-the-wrong-measure-of-reflectivity-for-modeling-climate/

    • “The temperature of the deep ocean has nothing to do with average surface temperature. Cold water sinks and as long as there’s any cold water at the poles, the deep ocean beneath the thermocline will remain a constant temperature varying from 0C at the bottom to 4C at the bottom of the thermocline.”

      The warmed water, doesn’t stay at bottom forever. And/or warmed water is lessening the cooling effect of cold water sinking.
      The main thing is this about long term changes in ocean temperatures.
      And I would say “global warming” or global temperature is about long term changes in ocean temperatures.
      It seems it was being said ocean warming was up to 90% of global warming, and here it’s saying up to 95% of global warming.
      And I think it’s 99% of global warming- or I am seeing progress.

      • gbaikie
        I don’t understand your statement, “The warmed water, doesn’t stay at bottom forever.” How does warmed water ever get to the bottom since it is less dense than than cold water? What are you trying to say?

          • gbalkie,

            Less salty water is usually so cold, having recently melted from ice, it still sinks to become part of the deep oceans repository of cold water. The cold water is pushed towards the surface, replacing water that evaporated. This arises because in the tropics, precipitation evaporation. This difference is what drives the thermohaline circulation which is often made to seem more complicated by calling it an arbitrary fresh water flux where they don’t have to acknowledge that there’s a steady flow of cold (3-4C) water replacing evaporation, even at the equator and the temperature of this cold water is unaffected by ‘climate change’.

            The warmest waters exit rivers are these are not salty at all. Water warmed by geothermal heat quickly rises to the surface and has little influence on the average temperature of deep ocean water or the fact that the deep ocean is insulated from the thermal mass comprised of surface waters and the bits of land that poke through and whose temperature sensitivity to forcing is what we care about.

          • html interpretation removed some text. It should be:

            This arises because in the tropics, precipitation is less than evaporation while in polar regions, precipitation is more than evaporation.

  12. Also, if an earthquake is picked up by seismometers and it appears to come from an uninhabited area of the earth, then the accuracy of the method determining the location is very poor.

    See: http://www.corssa.org/export/sites/corssa/.galleries/articles-pdf/Husen-Hardebeck-2010-CORSSA-Eqk-location.pdf
    To realize the problems researchers have in locating the source of an earthquake.

    Still, with post normal math, you can call up the use of large numbers and average out the he!! out of the data and get the answer you want.

    • Yet are they not measuring sound travel time from one recording instrument to another, verses from one source to different instruments?
      ( Once the sound is in the water its source would not be as relevant if you are measuring time from one recording instrument to another)

  13. Note the disclaimer:
    “AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.”

    It is appropriate that EurekAlert! should warn us that what they post may be inaccurate because the masthead illustration shows a seismogram with both P and S-waves. S-waves are not propagated through water and the article is exclusively about P-waves.

  14. “……as much as 95 percent of the extra heat trapped on Earth by greenhouse gases is held in the world’s oceans.“
    Sounds like confirmation bias. With blurb appeal. But technically what is the definition of this “extra heat” of which 95% is “held” somewhere, and is “held” the same as “warmer” for those who use more scientific terminology.

    • There’s so much wrong with this study. Much has been pointed out by others. But the essental point seems to have been missed (apologies if I did the missing): the temperature increase they “measured” is surely important, but it was not reported. If it was, say, 0.00015 deg C per decade, then it would take 100,000 years to go up by the 1.5 deg C that the IPCC and others say we must limit global warming to. Good luck with finding that much fossil fuel!

  15. The thread commenters at this point have identified the problems with this study. I doubt the study will demonstrate the propagation of error from uncertainties in the time of origin of the earthquake, through uncertainties in the path the first arrivals travel, to an uncertain temperature distribution along path. Tell us truthfully, please.

  16. Get yourselves a bucket of water and a heat gun. Try putting heat through the surface of water.The heat will not go through the surface of the water due to surface tension on the surface. Anthropogenic climate change is crap.rmb

    • Please show us the equations that establish how surface tension affects the rate of heat transfer into your bucket of water.

    • Heat gun is both radiant and convectional heat transfer. Convectional heat is confined to top 1 mm, and will cause evaporation heat loss. The radiant is near infrared up red light, and near infrared radiation can pass {and be absorbed] up to about meter depth.
      So if have deep bucket of water the near infrared radiant energy should warm the bottom of bucket and if one only had few inches of water, one could measure this effect more easily, but it require a lot energy to heat water- so having less water to heat, the more measurable the change temperature. Of course water can lose massive amount heat from evaporation, and so if sealed the top of bucket, one have less heat loss {cooling} from evaporation.
      Also if trying to melt solder, and have little bit water in pipe one is soldering, the water has to evaporate [it takes forever] before pipe can get hot enough for soldering to work.

  17. “we hope to contribute to the data about how our oceans are warming.”

    The poker player’s ‘tell’! At this stage of the research a rigorous scientist would be obliged to say “if our oceans are warming OR cooling”. I would have trusted the researchers more. I’ll call and

    Many here will rightfully ask what are the error bars. Here’s what is wrong with error bars in a sciency subject like gullible warming. They give illegitimate comfort to numerate readers. I see them differently. Since you really can’t give accurate error ranges in minestrone physico-chemical systems, it serves agenda science promoters to choose ranges that are tailored to their ‘needs’. To wit, IPCC’s climate sensitivity ranges for CO2. Empirical observations clearly lie below the range that they give and the only important feedback loop is how they will adjust temperatures to put the sensitivity in the middle of their ranges.

    Regarding the method (I did a shallow seismic BSc thesis on detecting voids (caves) in limestones in southern Manitoba’s karst topography) it could potentially work for temperatures but there are clearly confounding issues with ocean layers of higher/lower temperature/suspended clay silt (river outlets, seismic disturbance of bottom muds). Also, is it true the seismic waves move faster in warmer water? In rocks seismic moves faster the more dense the material.

  18. All that rumblings in the oceans and yet any man made ones are catastrophic for whales apparently. Even though Southern Rights swim all the way from Antarctica every year to get near high energy coastlines like the Head of the Bight in Australia. Always wondered how they navigate the noisy journey.

  19. How can every paper on climate science claim “It’s worse than we thought” and yet the human race is still trucking along, more food, producing more CO2, and nothing much new happening?

    I hate proxies like this. I guess it never occurred to them that there are natural conditions like salinity, current speed, or boundary layers that could EASILY impact their measurements – assuming their measurements are even accurate.

    When using proxies you always find exactly what you want because you get to choose any confounding factors that could have impacted the data.

  20. The leftist-run U.N. IPCC octopus never gives up their search for a pony in the manure. This time evil atmospheric CO2 is heating the oceans, which seems to be hidden to all observers, although they assure us that “as much as 95 percent of the extra heat trapped on Earth by greenhouse gases is held in the world’s oceans.”

    Sorry, atmospheric CO2 can’t melt an ice cube because of Planck’s Radiation Law, which gives its radiation emissions a Planck radiation temperature of -80C, too cold to even be found in Earth’s surface radiation. If it can’t absorb it, it can’t reemit it, and even if it did, it would be indistinguishable from the thermal radiation from dry ice, but worse, it would be only at a single wavelength not a power-wavelength profile and just end up being chewed up and spit out by the way hotter Earth’s surface. So if there really were some global warming, it couldn’t come from CO2, but the Sun, which the IPCC can’t admit because it would shut down their money-making racket.

    More and more WUWT readers are waking up to the -80C swindle about CO2 and cleansing their thinking of this sick hoax that’s been polluting so many sciences. I do the math in this free essay and lay the matter to rest. If only more people would read it, esp. A. Watts, who seems to be stuck in a mental rut that CO2 can cause global warming but it’s about the logarithm of its concentration:

    http://www.historyscoper.com/thebiglieaboutco2.html

  21. “…as much as 95 percent of the extra heat trapped on Earth by greenhouse gases is held in the world’s oceans”
    Riiiiight. Where it can’t be measured, but we “know” it’s there. Uh-huh. Because CO2 heat is special heat. It’s magical really, and is thus unencumbered by physical laws. How convenient.

  22. Anyone who wants to understand the factors influencing P-wave propagation through fluids needs to refer to the (oil) industry definitive standard on the topic, used almost universally for fluid substitution in rock physics. That paper is Batzle & Wang (1992).

    I would add here that I met Mike Batzle at a few SEG D&P conferences – he was a great guy, brilliant, helpful, supportive, modest and unassuming. His untimely death was very sad.

    • Quick Batzle and Wang calculation of the velocity through seawater.

      Assume pressure at 2000 m = 19.45 MPa
      Temperature = 10 degC
      Salinity 35000 ppm

      For salinity distributions see https://rwu.pressbooks.pub/webboceanography/chapter/5-3-salinity-patterns/

      These figures give
      Velocity = 1518.7 m/s

      change temp by +1 to 11 degC then velocity will be 1522.3 m/s
      change temp by +0.1 to 10.1 degC then velocity will be 1519.1 m/s
      change salinity +1000 to 36000 ppm then velocity will be 1520.0 m/s
      change pressure to 2100 m (20.43 MPa) then velocity will be 1520.3 m/s

      Pressure varies according to the density of column of water above – which varies with temp and salinity.

      a 0.1 degC change in the entire water volume will give a smaller velocity change than either a 100 m equivalent pressure change or a 1000 ppm salinity change. And 0.1 degC temp anomaly would be huge in global warming terms. None of the velocity changes above would be detectable from earthquakes (or even from controlled sources).

      Its bollocks as far as I can see, notwithstanding the problems of detecting the direct water column arrival which won’t be the first arrival from an earthquake (see my post below).

  23. Isn’t there a delay between the earthquake starting – and the monitoring station being told the clock has started?

  24. The technique is largely nonsense. The speed of sound in water varies with both temperature and salinity. Without knowing salinity (which varies above 700 meters depth per Argo depending on surface rainfall—in fact Argo salinity probes are calibrated at the 1000 meter drift depth) you cannot infer temperature. Only if the seismometer acoustics were placed below 700 meters depth would the technique have any validity.

  25. In the 70s I was employed with a marine seismic survey company that used Shoran (and similar systems) as a navigation tool for dynamically locating survey ships as they undertook grid surveys offshore. Atmospheric propagation properties could easily change often depending on time of day weather and local flora – tropical forests sucked the hell out of signals! So I’m sure, while this method in principle is sound, there are too many unmeasurable variables. One being how can they be sure that an earthquake occurring in the same location several times over a period is actually has the exact same focus as it’s previous iterations. I would doubt that after the strata have settled after one earthquake the next pressure/fracture point is unlikely to be in the same spot. Then you have the intervening ocean environment: changes in salinity, depth, pressure, temperature, flora and fauna. Not a happy recipe for success.

  26. From the above article: “. . . as much as 95 percent of the extra heat trapped on Earth by greenhouse gases is held in the world’s oceans.”

    Ummm . . . I guess you are referring to that net 0.9 W/m^2 that suddenly appeared in the Kiel & Trenberth 2008-2009 revision of their diagram of Earth’s “energy budget”, you know, the one that shows the balances of W/m^2 power fluxes (not energy flows). This is also the 0.9 W/m^2 that so alarms Bill McKibben (he assess it to be “about three-fourths of a watt”; see https://wattsupwiththat.com/2020/09/08/bill-mckibben-talks-up-the-alleged-climate-change-extreme-weather-link/ ).

    So, the above two paragraphs, taken together, leave only about .05*0.9 W/m^2 = 45 milliwatts/m^2 “extra heat” to warm Earth’s total land surfaces and total atmosphere. And—need it be mentioned?—this would assume one can track the W/m^2 fluxes to a precision of .045 W/m^2 out of 341 W/m^2 incoming, or about 1 part in 10,000.

    Is it any wonder that I’ve started to feel cold lately?

    • “So, the above two paragraphs, taken together, leave only about .05*0.9 W/m^2 = 45 milliwatts/m^2 “extra heat” to warm Earth’s total land surfaces and total atmosphere. ”

      And don’t imagine Bill McKibben including Geothermal heat.
      Feeling even cooler.
      But let’s face it, 15 C is chilly.
      And we in an Ice Age- which has more temperature extremes.
      Can only hope that it gets warmer.

  27. This is very interesting indeed.
    A new fully independent way to measure ocean temperatures in 3D? This could cause some serious fear and insecurity among the activist-custodians of current ocean temperature data. It could put Josh Willis into prison for example.

    Somehow I suspect it will be like the CO2 satellite measurements. The results will not be kosher so it will fade from view. Sad but true.

  28. The traditional thinking is that the visible and shorter wavelengths penetrate much much further and cause more heating. Near and far IR from the sun may heat the very top inches but that is all. Back radiation from CO2 is miniscule compared to the sun.

    What this really means is that for detectable temperature increases, CO2 is not the issue, sunlight or some other effect is.

    • The heat capacity of the entire Earth’s atmosphere is about 1/1000 the heat capacity of the global ocean.
      A column atmosphere of 1 square meter area will contain about 10000 kilograms.
      A column of seawater with the same mass will extend about 10 meters down from the surface.

      The specific heat capacity of seawater is about 4 times the air above.
      So the heat capacity of the entire atmosphere above the ocean is matched by seawater to a depth of 2.5 meters.
      Taking the actual global masses of atmosphere vs ocean, the oceans will have 1000 times the heat capacity.
      If you added enough energy to heat the atmosphere by 1K, the same amount of energy would increase the ocean temp by 0.001 K.

  29. For this to work the velocity of propagation of the earthquake energy through the earth would have to be a constant. If this is not the case, then the exact time that the earthquake event took place is unknown thus affecting the difference in time between the arrival of the seismic energy in the earth as against in the water. I do not know if seismic energy velocity through the earth is constant but it would seem unlikely given the different densities of strata through which it must travel.

    • Peter
      Seismic velocity through rocks is NOT constant, varying with the type of rock, and in the case of sedimentary rocks, with the compaction or induration. In general, velocity increases with density, meaning the velocity increases with depth in the mantle.

  30. Rough trend of 0.035K per decade which would be like 0.35K from year 2000 to 2100. But that’s just a rough visual estimate not accurate because I don’t have the full print or data.

    The time period and clock accuracy etc. would also affect the accuracy.

    https://www.google.com.au/imgres?imgurl=https%3A%2F%2Fscience.sciencemag.org%2Fcontent%2Fsci%2F369%2F6510%2F1510%2FF3.medium.gif&imgrefurl=https%3A%2F%2Fscience.sciencemag.org%2Fcontent%2F369%2F6510%2F1510&tbnid=a5J8Rkv5xIaZqM&vet=12ahUKEwiOvJTC-fjrAhXbCXIKHW8dAzAQMygFegUIARCsAQ..i&docid=TDmWTWd6ga09oM&w=289&h=440&q=%22Seismic%20Ocean%20Thermometry%22%20Wenbo%20Wu&ved=2ahUKEwiOvJTC-fjrAhXbCXIKHW8dAzAQMygFegUIARCsAQ

  31. The location of the center of the earthquake must be known with high precision for this method to work. Since this is done by triangulation using several seismic signals, there is some uncertainty in calculating the center. Then the sound wave travels through the rock for some distance, and then through the water. The depth below the sea floor must be known as well as the path of the sound wave so the differing velocities can be accounted for. Water depth and salinity also affect the accuracy. Did they do some error analysis?

  32. “as much as 95 percent of the extra heat trapped on Earth by greenhouse gases is held in the world’s oceans.”

    This is utter garbage. IR can not penetrate water, the oceans can not absorb global warming. The oceans can not hinder CO2s ability to t warm the troposphere.

    Come on, we all know this, this has been discussed many times, even Real Climate did a piece on it.

  33. Basic problem of the method – first arrival times from earthquake to sensor will be through rocks not through the water. This is because the water velocity is about 1500 m/s whereas typical crustal rocks lie in the range 2500 (shallow) to about 3500 m/s (deep sediments). Limestones and evaporites are much faster, as are crystalline rocks, some approaching 6,000 m/s. The first arrival is always through the fastest medium (obviously).

    In order to reliably measure an arrival through water from an earthquake you first need to establish the distance to the quake – this only comes approximately from triangulation. Then you need to identify and observe the water-borne signal. That will never be a water only arrival as earthquakes are in rocks, so some of the signal will always be through the rock medium. Identifying the water borne signal within the seismogram will also be difficult. Finally without a repeatable source in a fixed location over many years you need the point of origin to get the distance in order to compute the velocity from v = d/t. You also need to be able to apply tomography to invert the travel time data to velocity – again you need the distances and a very large number of (accurate) travel time arrivals.

    Complete dud as a method. You could only (possibly) make this work to detect velocity changes within the ocean with controlled sources in the ocean, permanently deployed. Even then, the influence of temp on velocity is pretty small – other factors such as salinity will be far more important (see Batzle and Wang, 1992 for the physics).

    Its a dud. Chasing grant money is what it smells like.

      • Source to recording instrument one would clearly be to imprecise.
        Yet us that what they are doing?

        Would it not be more logical to measure time between recording instrument one, in the water, and recording instrument two? ( And are those locations fixed )

        • To get long enough travel distances would need really big charges in precisely known positions. Nuclear depth charges would be perfect.

  34. “as much as 95 percent of the extra heat trapped on earth by greenhouse gases is held in the world’s oceans”

    According to an Open University (UK) book I have on Seawater :Its composition, properties and behaviour

    “The long- term stability of the distribution of temperature within the ocean means that sections and profiles of average temperature do not change significantly from year to year. This stable thermal structure is maintained by the continuous three-dimensional motion of the global system of surface and deep currents”

  35. Another factor nobody seems to have mentioned: doppler effect. The travel time is c. 2200 seconds, the difference about 0.1 second, equal to 1/22000 of 3300 km = c. 150 meters distance, so an uncetainty in the location of the eathquake of 150 meters is enough to wipe out any temperature signal.

    But this distance uncertainty could also be due to ocean currents. For the travel distance to change 150 metes over a 37 minute period only requires that the average velocity vector of the water along the propagation path changes by 0.13 knots. And note that this was in the Indian Ocean where ocean currents vary strongly during the year and between years due to the monsoon.

    To summarize, the travel time is affected by:

    1. The exact position of the quake (which will not be the same for different quakes)
    2. The depth of the quake (dito)
    3. The structure of the rocks a) along the path from the quake up to the ocean bottom and b) along the underground path (dito)
    4. The salinity of the ocean along the propagation path (dito)
    5. The movement of the ocean water along the propagation path (dito)
    6. The temperature of the seawater along the propagation path.

    To measure (6), (1) through (5) must be known with extremely high precision.

  36. It seems like a nice idea, earthquakes a decently known distance away that can be triangulated with other seimometers. Measure the difference in time between the rock wave and the water wave which is easy with just a quartz crystal controlled timer, assuming the data storage has a resolution of a hundredth of a second or better.

    The real problem is going to be the signal path. The path through the rock should be constant barring any major seismological event between the source and seismometer. But the path through the water is questionable. The first thing I would look for is the El Nino, La Nina Pacific oscillation in the data. I would also want to see data on the depth changes of the thermocline from the Argus floats.

    If the water wave path is deep water then this might show a temperature rise in the deep ocean. It should still be rising from the little ice age.

    • ” It should still be rising from the little ice age.”

      Or it could be sinking as water from the MWP upwells and is replaced by LIA water. The turnover time for the deep sea is 800-1,600 years, it varies geographically.

  37. The proposition assumes a point source where P waves convert to sound/water waves.

    The rupture zone/source for the 2004 Sumatra earthquake was perhaps 1400km long.

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