Remote Sensing of Real-Time Volcanic Activity Part 1: Webcams and Thermal Cameras

Thermal camera view of Stromboli volcano, Italy (real-time: A – 00:10 UTC on March 15, 2013.

Thermal camera view of Stromboli volcano, Italy (real-time: A – 00:10 UTC on March 15, 2013.

Often, volcanoes are difficult to reach and it is not possible to have observers with a line of sight view of the volcano. Remote sensing of volcanoes and their products, pre-, syn- and post- eruption, provides a unique method to systematically analyze how they change with time and with the aim to detect possible precursors to significant events.

So the first question is “What is remote sensing?” Well, it is:

‘the science and art of obtaining information about an object, area or phenomena through the analysis of data acquired by a device that is not in contact with the object, area or phenomena under investigation”

Remote sensing data can come from ground-based equipment, airborne surveys and spaceborne satellites and their sensors. Here, in this article, I report on some of the capabilities from ground-based equipment, such as webcams and thermal cameras, that can detect thermal signals and detect/measure volcanic plumes and clouds in real-time. The data from this equipment can then be used for systematically detecting changes in volcanic activity.

Ground-based remote sensing equipment

While webcams and thermal cameras are not the only instruments and equipment that can be used to detect and analyze real-time volcanic activity, they have become some of the most available and used tools for remote sensing of a volcano, from the ground.

The number of webcams viewing a volcano is now rapidly increasing, with some volcanoes having multiple cameras, either viewing the volcano from different angles or with different zooms. For example, Shiveluch volcano in Kamchatka.  This volcano is monitored by the Kamchatka Volcanic Eruption Response Team (KVERT,

Online, there are three webcams that provide real-time access views of the volcano, see Figure 1. Here, the three views all are of the same side of the volcano but at very different scales. Figure 1A shows the camera with lowest zoom and hence greatest view, with the volcano between the trees.

Figure 1C is has the most focused view of the volcano, with the dome in the centre of the image. Also, in Figure 1, the three views are all cloudy, for the time on March 18, 2014 (04:14 – 0:16 UTC). Also, note that these are daytime views of the volcano and as such, often webcams, are unable to capture volcanic signals are night, but this is not always the case. Some webcams can capture night-time activity.

Figure 1. Three webcam views of Shiveluch volcano on March 18, 2014. A – 04:15 UTC from Shiv1 -; B – 04:16 UTC from Shiv2 -; C – 04:14 UTC from Shiv3 -

Figure 1. Three webcam views of Shiveluch volcano on March 18, 2014. A – 04:15 UTC from Shiv1 –; B – 04:16 UTC from Shiv2 –; C – 04:14 UTC from Shiv3 – Click to enlarge image.

To be able to capture the thermal signals from a volcano in a webcam at night, there are several items that need to happen: 1) the target is hot enough to elevate the webcam pixel data so it is brighter than surrounding ones; 2) webcam wavelength is designed to be susceptible to thermally hot targets; and 3) the weather conditions are such that no local cloud obscures the signal.

Let’s take the three webcams for Shiveluch again from Figure 1. Now a night-time view is provided, March 15, 2014, Figure 2. Here, the images are within 5 minutes of each other. Note that the Shiv2 webcam, Figure 2B, shows a strong thermal signal from volcanic activity at the dome on Shiveluch volcano. The other two show no thermal signals from changes in brightness of the webcam pixels. Here, Figure 2B’s webcam is more susceptible to the thermal signals occurring at the volcano.

Figure 2. Three webcam views of Shiveluch volcano on March 15, 2014. A – 10:55 UTC from Shiv1 -; B – 11:00 UTC from Shiv2 -; C – 10:59 UTC from Shiv3 - Click on image to enlarge.

Figure 2. Three webcam views of Shiveluch volcano on March 15, 2014. A – 10:55 UTC from Shiv1 –; B – 11:00 UTC from Shiv2 –; C – 10:59 UTC from Shiv3 – Click on image to enlarge.

Additional examples, from my blog, on thermal signals can be found at the following links:

Algorithms can be designed to detect for these changes in thermal signals and provide an event detection system for changes in volcanic activity. Lessons can be learnt from the satellite remote sensing community in terms of change detection that can be adapted to webcam imagery. Then the webcam data can be used to detect volcanic activity in real-time. The next stage would then to be able to calibrate the data from brightness values to potential elevated temperatures.

Webcams can also be used to detect and measure volcanic plume height, as long as the altitude of the top of the webcam image is known. Also, for this the plume/cloud’s direction has to be assumed. Many researchers have used the plume height of the eruption plume to measure eruption rates (e.g. Sparks [1997] and Mastin et al. [2009]). If the plume is vertical in the plane of the camera, then the eruption rate method will be most accurate. If away from the camera, then the rate method will be an under-estimate and if towards the camera then the method will be an overestimate of the rate. Figure 3 shows some example of plumes captured by webcams, highlighting the issue of webcams being too close and the plume leaving the field of view.

Figure 3. Webcam views of Popocatepetl volcano, Mexico (real-time view: A - 00:10 UTC on April 18, 2013; and B –19:41 UTC on May 7, 2013. Click on image to enlarge.

Figure 3. Webcam views of Popocatepetl volcano, Mexico (real-time view: A – 00:10 UTC on April 18, 2013; and B –19:41 UTC on May 7, 2013. Click on image to enlarge.

Additional examples, from my blog, on volcanic plumes/clouds can be found at the following links:

So webcams, while sometimes limited, can still be very useful for remote sensing of active volcanoes. They are usually designed for their most optimal use in the day-time, but some of them can be useful at night, but this depends on wavelength, thermal signal strength of the active volcano and local weather conditions.

There are some camera systems, set up at active volcanoes, which can measure in the thermal infrared and hence are very useful, day or night. Figure 4 shows a couple of examples of the thermal camera set up at Stromboli Volcano by the University of Florence. Figure 4A shows an image captured at 00:10 UTC (local nighttime) on Mar 15, 2013, where a new explosive event from the volcano has occurred. This image has been captured at a most opportune time, as Figure 4B shows that at 11:50 UTC on March 5, 2013, an explosive event has just happened as the slopes of the volcanic summit are at elevated temperature than the surrounding region.

Figure 4. Thermal camera views of Stromboli volcano, Italy (real-time: A – 00:10 UTC on March 15, 2013 and B – 11:50 UTC on March 5, 2013. Click on image to enlarge.

Figure 4. Thermal camera views of Stromboli volcano, Italy (real-time: A – 00:10 UTC on March 15, 2013 and B – 11:50 UTC on March 5, 2013. Click on image to enlarge.

These two images in Figure 4 show the timing of the data captured is critical for understanding the signals measured and the repeatability of the volcanic signals. Also, the data is only as a jpeg, and not raw data, so the colors seen would need to be converted to approximate temperatures using the scale bar as a guide. Spampinato et al. (2011) provide a detailed review of the different data processing, levels of accuracy, applications and methodology of data collection for volcanic surveillance with infrared cameras.

Thermal cameras provide an excellent dataset for remotely measuring a volcanoes activity. They are often expensive and as such only a few exist for real-time analysis and they are usually used in short term campaigns, either from the ground or in overflights. However, satellites and their sensors can provide a spaceborne view of what a volcano is doing, in terms of thermal signals, volcanic ash release, sulfur dioxide flux and deformation signals.


Peter WebleyDr. Peter Webley is an Assistant Research Professor at the Geophysical Institute, University of Alaska Fairbanks. Dr. Webley’s focuses upon using remote sensing data to analyze natural hazards, such as volcanic events, forest fires, landslides and coastal erosion. Dr. Webley has designed new mechanisms to visualize the development of volcanic ash clouds. He has taken the three-dimensional dispersion model simulations that used to be visualized on two-dimensional maps and displayed them in their original three-dimensional form. Dr. Webley has been the guest editor for two special issues of the Journal of Volcanology and Geothermal Research (JVGR) in 2009 and 2013. His paper collaborating on eruption source parameters, Mastin et al. (2009) and listed in his selected publications is the highest cited publications in JVGR since 2008 with over 95 citations.

Recently in 2013, Dr. Webley, along with Dr. Jon Dehn, an Associate Research Professor at the Geophysical Institute, University of Alaska Fairbanks, formed a company called V-ADAPT, Inc [Volcanic Ash Detection Avoidance and Preparedness for Transportation], (, from their research at the University in analysis of volcanic activity and dispersion modeling of volcanic ash clouds. V-ADAPT, Inc. provides data, tools, analysis, and risk assessment of volcanic ash for the aviation and other transportation industries. They offer a comprehensive system to help in planning and response to volcanic eruptions for its clients. It is based on over 20 years of the founders’ experience in mitigating hundreds of eruptions in the North Pacific. The company focuses on volcanic hazard assessment and scenario planning through research and development, consultancy and service-orientated web-based tools.


Spampinato, L., Calvari, S., Oppenheimer, C., and Boschi, E., 2011. Volcano surveillance using infrared cameras. Earth-Science Reviews106 (1), 63-91.

114 thoughts on “Remote Sensing of Real-Time Volcanic Activity Part 1: Webcams and Thermal Cameras

  1. nice post – I am now waiting for parts 2,3,4,5 and 6 (it only says part 1 – not part 1 of 6 but I thought I’d see if we can get 5 more posts – though I don’t know if there are 5 more sorts of remote sensing, there seem to be at least 3 more: satellite, gps, and seismometers (are there others?)

    • My lips are sealed.
      But I for one would love many parts. So remember to ask Peter nicely for more parts 🙂

  2. Thanks for the post. It is interesting to see how the professionals utilize something as simple as a webcam to aid their research (and monitoring) of volcanoes

  3. Thank you very much for this interesting post! 😀
    Speaking about real-time: Often the webcam refresh rate seem agonizingly slow. Why can´t we (the volcanoholic public) get live-stream all the time? I suspect it is a matter of costs and infrastructure, but how much more expensive would it be?
    And another question: How often did we get fooled and over-excited by what turned out to be weather clouds. Is there a simple image processing method to distinguish weather clouds from ash clouds on a webcam screenshot? 😉
    Looking very much forward to the next part(s)!

    • Oh… I will definitely put on my thinking cap now!

      On behalf of everyone at Volcanocafé I would like to extend our thanks to Peter for writing this!
      And you heard him, write a wishlist 🙂

  4. Thank You Dr. Webley! Very nice article!.

    My 2 cents comment for all. Many commercially available digital cameras and web-cams use CCD imaging chips that are sensitive in the near infrared. Many times these cameras have an IR filter affixed over the chip in order to keep them from responding to that part of the spectra. For those who are into “hardware hacking” and reconfiguring inexpensive imagers for other purposes (astronomic photography etc.) they can be removed… though you can kiss any warranty goodbye once you open up the device and start messing with the internals. There is an entire branch of the hobbyist field that deals with accessing and retrieving images from the CCD chip, going as far as to calibrating the FOV into arc-seconds (based on the dimensions of the chip face) in order to measure angular separation of the objects being photographed. Most of this is done using existing astrometric calculations, replacing the size of the imaging plate with the CCD chip size. I had one “project” I was tinkering with where I was going to use the head carriage of an old gutted floppy drive to carry a CCD assembly into and out of the focal point of my telescope. After I started having concerns about whether my telescopes drive assembly could handle the extra mass, I sidelined that idea and discovered Eyjafjallajökull making press. How can you pass up a distraction like that?

    • Yes, the FOV and the CCD chip as well as the IR filter does make some of the digital cameras harder to use for detecting thermal signals. Sometimes its the cheaper cameras, without the extra gadgets, lens etc that work well.

    • 2 decimal p’s worth from me as well. A large part of my real life work is designing optics for remote sensing, although mostly remote sensing people and vehicles rather than volcanoes. We work with visible, near IR, short wave IR, mid wave IR and long wave IR. The last two are considered “thermal” because black bodies have significant emission in those bandwidths around ambient temperature. Visible, NIR & SWIR generally depend on reflected light but erupting volcanoes, being decidedly warmer than ambient, can be effectively self luminous in those bandwidths as well.
      SWIR, using InGaAs sensors, has become a very important new field in the last few years. This typically extends the spectral range from ~700nm (deep red) up to ~1700nm. Silicon based sensors such as CCD or CMOS are effectively limited to ~1000nm because the substrate becomes transmitting above that. The big advantage of SWIR is that it has excellent visibility through mist and is undisturbed by atmospheric turbulence. So far, the dominant interest for these things has been border surveillance but it would be interesting to see one pointed at a volcano.

      • One would think that IR sensors intended to track exhaust for heat seeking missile guidance should be usable for the plume from a volcano with a bit of tweaking. Valid idea?

        • Yes indeed. Many military thermal imagers would make excellent volcano watchers, but the military tend to work on a different budget to vulcanologists.

          • But at least the development work on the sensor is for the most part, paid for. Then it’s just a matter of procuring the sensor and getting it built into the appropriate device for monitoring purposes.

            In the book “Some Birds Don’t Fly,” Gary Paulsen relates a story about a couple of engineers with an IR missile setting on a pair of saw horses, gleefully watching the seeker head track secretaries walking down the hall and taking note of which ones the seeker preferred to track.

            • 8-14 micron “uncooled” LWIR sensors are getting relatively common. Companies like FLIR in the US and e2v in the UK are making reasonably low cost non-military grade cameras for fire rescue, security etc. These are generally wide to moderate field of view. Long range narrow field of view optics present some interesting optical challenges. Fixable, but not cheap.
              Using these high tech gizmos around the office to find out who is “hot” is not an approved application 🙂

            • Just for clarification – I put uncooled in quotes because they are usually warmed. Typically 30-40 C. Not many seem to know that, even in the industry. Older LWIR sensors and most current MWIR sensors are deep cooled to only a few degrees above absolute zero. This raises some interesting issues and means that MWIR isn’t likely to become widely affordable any time soon.

            • I can agree with the unapproved usage. but it’s just a story from a book about some bored engineers.

              Back when I was fiddling around with a CCD imager that I had liberated from a webcam, one of the things I played with was colling the assembly with a TEC/CPU heatsink and fan. It looked to have merit though I figured that the vibration from the fan, though small, would give me issues later on. The goal was to reduce the noise of the CCD.

              I later made one really kludged together 12 air-conditioner. It actually worked, though the efficiency of it was pretty miserable. The motivation behind that was from my experience in dealing with the aftermath of Hurricane Ivan. We had resorted to taking short naps in the truck as a temporary relief from the heat.

          • If anyone ever gets a chance to read that book, I think you will find it quite entertaining. It has several stories relating the vagaries of working on the development of ballistic missiles (“Cooley and the Pink Cloud”) to an inadvertent surface to air engagement against a freshly tagged condor that was mistaken for a target drone. The SAM achieved “skin to skin” and obliterated the bird in a puff of shrapnel. A few minutes later the target drone flew into the target area and they started questioning what they had shot. It wasn’t until the wailing naturalist called them up that they found out that they had just shot the bird he had just tagged. (Metal band around the leg, which in my experience means that the radar system driving the show was quite good)

  5. Very nice article Dr Webley, thank you for lifting a part of the veil.
    As you may know I’m an avid Gnu Octave/Matlab user. There are some very useful functions in both programms to deal with image processing.
    What type of software do you use for image processing ?

      • In beginning… “light of sight” or “line of sight”
        I know the latter from normal VHF useage.
        We are talking such ? 😉

        • Post edited for the benefit of myself and our other pedants…
          Definitely “line of sight;” though “light of sight” should be a line from a pome 😀

          DragonEdit: Or from a pome-grenade?

          • Hmmmm… Pome is a deliberate misspelling/ pronuciation of poem 🙂
            I think we may be in danger of losing the joke in translation…
            Since I’m in an OT yet chatty mood I’ll expand…
            Almost all jokes rely on an intimate knowledge of the language to understand the nuances/puns/metaphors/slang and be able to “make the switch…”
            My Spanish is conversational/ street level,(which means if I don’t understand I am able to ask for clarification, and if I don’t know how to say something I can ask how to say it) and I have been told any number of Spanish jokes…
            None of them have ever raised so much as a chuckle, the wordplay is far beyond me, and I think one would have to be damn near fluent to get it…

            DragonEdit: Poem-grenade? Sounds Vogon to me… “Oh freddled gruntbuggly, Thy micturations are to me As plurdled gabbleblotchits on a lurgid bee. Groop, I implore thee, my foonting turlingdromes, And hooptiously drangle me with crinkly bindlewurdles, Or I will rend thee in the gobberwartsWith my blurglecruncheon, see if I don’t!”

            • To cut a long story short I didn’t get the pome/ grenade references at all… 🙂

            • Pomegrenade is a rather tasty oriental fruit. Literally means Pome de Grenada and is the main ingredient of Grenadine.

              The above is the poetry of Vogon Proztetnik Jeltz. (Hitch-hikers Guide to the Galaxy: Douglas Adams)

            • If we’re lucky they’ll throw us out of the airlock.
              And what if we’re unlucky?
              The captain will read us some of his poetry first…

            • Oh that pomegranate…
              If I had to pick a favourite fruit which was all about the seeds I would go for cherimoya/ custard apple:

            • Oh and don’t get me started on Vogon poetry…
              It’s just a pale impersonation of Lewis Carroll:

              The Hunting of the Snark: An Agony in Eight Fits.

    • Seeing as it’s in the middle of a swamp, and this swamp is on top of several thousand feed of sediment accumulation, I’m thinking it’s the vestiges of a mud volcano occasionally lit by Phosphine or Diphosphane. Both are also byproducts of decomposition, and both can ignite upon contact with the air. Add a methane seep to it and you get flame.

      Hydrocarbon seeps are not uncommon in the Gulf of Mexico basin. In fact, the USCGS has on occasion gone chasing after the source of an oil sheen to cite the violator only to come up to empty water, with no ship to blame. On some Florida beaches, early explorers noted tar balls… long before the era of oil exploration.

      From the article: “Many parts of this vine-tangled jungle are as inaccessible today as a century ago

      Extremely true. My maintenance district doesn’t take me as far as Wakulla, but Ponce de Leon is a small town along the interstate that I regularly use. The “bottom land” around that area is quite pristine and imagining the explorer Ponce de Leon’s party tromping around in that morass of swamp land and brush gives me chills. Even today you had best take a machete with you if you plan on making forward progress through it. (Clearing brush and vines and dealing with whatever may be lurking in it)

      The basement limestone in this area is cut by the Tallahasse Fracture zone as per the research of Bryan P. Stephens in “Basement Controls on Subsurface Geologic Patterns and Near-Surface Geology across the Northern Gulf of Mexico: A Deeper Perspective on Coastal Louisiana” Bryan P. Stephens (2010) This tends to facilitate the formation of karst topology, and increases the occurrence of springs and sinkholes. The Port St Joe fault has led to the formation of many sinkhole lakes north of Panama City, and of all the ancient transforms, is still somewhat active.

      Specifically, check out Page 8 of the document.

  6. One thought for thermal detection algorithms – how do they handle sunrise/set if that happens to line up with the volcano ?

    • Edward, there are s suite of thermal detection algorithms from the satellite side that could be applied. They are looking for change detection. If applied to a webcam, then some corrections would be needed for the day-time versus night-time data.

  7. A small animation for the fun using the GPS charts from IGN.

    There’s a change of chart type (1 to 2) at about 13 s

  8. Dr Webley. Thank you so much for a very informative Post and I am looking forward to more. I am not too good at the technical side of things but I do use most the web cams available. I have never really understood why some volcanoes are monitored using excellent live cams and such as Hekla in Iceland and Sakurajima in Japan. I suppose it is costly to set up and maintain. I would have thought that Italy would use such systems for Etna and Stromboli, or even Vesuvius but again I guess it is all down to finances.
    If one of say, the Alaska, volcanoes started erupting could a live cam be easily set up such as the one in El Hierro? I am always a little disappointed when I go to the Kilauea cam. as well. That would be so fascinating to watch rather than the static pictures.
    However this is just a personal observation .
    I really appreciate the time you have put in for this post and am always a little in awe of seeing a professional writing for this blog. Amazing. Thank you again.

    • I’m a different kind of professional, but I think I can answer part of that. It all comes down to bandwidth. Sure, you can grab the imagery, but how do you get if back to a place where you can use or distribute it? Any solution you can come up with will be heavily influenced by the cost of moving data. Cell phone networks can overcome some of that, but you have subscription fees and bandwidth limitations. A private WiFi network is good for about 26 miles if you push the technology envelope. (dishes on the two antennas boresighted on each other etc./.) If you resort to lower frequency RF data links, then you open up a longer range, but you run into issues with custom built equipment and FCC licensing. (or the countries equivalent bureaucratic layer) In addition, you have to have spacing on either side of your carrier signal in order to move the data with whatever modulation scheme you have adopted. You could go with spread spectrum but that incurs it’s own technical overhead and complicates matters. (But you get a bit of resilience to noise and data link security from the data slicing part of it)

      By this time, you are into the cost-benefit side of the endeavor, but it still boils down to bandwidth. Imagery costs quite a bit compared to normal data streams.

      BTW, Inmarsat can quickly bust the budget, but it is doable… at lower bandwidth requirements. Inmarsat was built in order to carry telephony, and that is a much lower bandwitch than what video requires. I’ve worked with satellite data transmission systems before, but the system I used was moving the equivalent of ASCII data back and forth from platform to platform. On a more advanced realm, satellite Internet is becoming a commonly used system. The bandwidth is acceptable, but you one inherent problem. Data latency. With satellite Internet, this takes the form of establishing the connection (using TCP). Once it is established it’s pretty fast. But any move to an alternate port is going to take time to set up and can cause a loss in the link. TCP is meant to be pretty autonomous and controlled by the two network cards as they negotiate the connection. One part that is usually missed is that all the intervening equipment has to do the same to adjust to the traffic load. Once the satellite carriers solve that problem, they are going to rule the market. But then you are back to cost-benefit… and the effect on your budget.

      • I am always in awe of you Lurking. Your technical knowledge of so many things which are way out of my league astounds me. So much experience in so many fields. I will admit to not realising the problem of bandwidth. But then I am not very good at understanding my own cell phone so anything more complex and I feel my brain fogging up 😀
        As to the professionals I was referring to I did mean Volcanologists. We have so many professional people here each with their own expertise. Each adds a different slant on our common interest in volcanoes. It surely proves how interwoven the sciences are and how vital it is in schools to educate children that learning should not be about subjects set in little isolated compartments.
        OMG! I am almost ruminating. Far too late and I have not had a coffee since dinner time . Time for a hot chocolate and then bed.

        • Well, RF technology (specifically radar) was my field for 20 years and you tend to pick up on stuff if you are exposed to it long enough.

    • Often it is bandwidth to get the data back from the remote locations. If you have a good source of power and web-based fiber optic cables then you can get data back at sec intervals or even stream continuously. if you have limited ability to send the data back, then you might be able to send data every min or 5 minutes. Then if you are really limited, you may need to turn the camera on, take picture and turn off again to save power.

      • Peter pointed to something really important here.
        Equipment run on electricity and at remote locations you either need to be able to generate it, or have a battery sufficient to run the equipment for a long time.
        Especially as far north as Peter and I am you have quite a bit of a problem with both strategies. Wind and Ice will often build up on solar cells or windmills, and the darkness during the winter would make solar cells a bad choice during the winter. So if you go solar you need much bigger and more expensive cells, and to top it off you would need to load balance them for when the summer comes and there is light almost 24 hours a day.
        If you go with batteries they would need to be pretty large to last for a long time, and to make matters worse, batteries hate cold. So, you would need to insulate them well and use even more electricity to keep them warm and cosy.
        In the end you will find that you would need to invest a lot of time and effort into constructing equipment with as minimalistic energy requirements as possible if you are going to place them away from the beaten track or you would have to go with equipment that cycles through awake/sleep periods to save energy like Peter mentioned.
        Remember that in Alaska (as example) you can probably only load the batteries once a year due to weather conditions.
        Now, remember that the same equipment is often made to also work well in the opposite condition, extreme heat. Making instruments, a rather odd art of compromises.

        • Kerosene is the answer. We need a small generator running on kerosene. This is Energy Chemical storage. You only have a marginal problem with the cold (low parafinn point). A small motor and an alternator.

            • Price is of the essence too. I always apply the KISS system. Fuel cells are nice for the Nasa guys. How are you going to haul liquid H2 & O2 in, say, Camerroon? But you will find fuel anywere as long as there is a car….

            • Yes, price is of an essence. It is a trade off, reliability vs price.
              The Fuel Cell will be more reliable and use fewer components and less fuel.
              And they are starting to become rather cheap nowadays, and it is surprising in how many places you can find gas nowadays.
              For instance in Cameroon you can buy it from the same company in Buaea that sells gas to the local welders and that city is pretty much next door to the volcano. The world is rapidly becoming a smaller place. Otherwise a flying in with a bottle of gas is not that heavy really, remember how little gas those buggers really use.
              But, being able to provide both systems together with a pure batterypack solution would be best. And the ever best solution is to use as little power as possible.

  9. Hi Dr Peter,
    Thanks for the wonderful article, I have been following your blog via the VC fracbook page, but this is a great introduction to the fundamentals of remote sensing.
    @ Edward (and Dr Peter) how about COSPEC (correlation spectroscopy) for another remote sensing method; it’s for analysing gas emissions. I believe there are more modern methods, so perhaps Dr Peter could give us a run down…

  10. With the innovation of digital gadgetry, sensor technology has had it’s own advances.

    This is a plot of an accelerometer that I have been messing around with.

    Those regular spaced seismic events aren’t anything fancy. Just me dropping a 4.54 kg weight a distance of one meter at a range of 5 meters from the sensor in damp sandy soil. In previous tests, I have noted that the “first motion” is a negative swing, signifying that the initial stress wave was the ground “pulling” away from the sensor.

    In actual quakes, the geologists use this “first motion” part of the waveform from several seismographs to work out the focal mechanism of the event causing the quake. In real quakes, there will be a two compressive quadrants where the first motion is towards the sensor, and two extensive quadrants where the motion is away from the sensor. Plotting out the spatial relationships of this verses the locations of the seismos yeilds the focal mechanism that tells up what sort of fault system that the quake occurred on. (Thrust, reverse, strike-slip, oblique etc).

    In this particular test, the sensor was attached to a screwdriver pushed into the ground. I plan on taking my screwdriver and sensor with me out in the field and If I have an opportunity, to plant it near a construction site for a few minutes so that we can get an idea of the very noisy seismic environment of construction equipment.

    About the different spike amplitudes… that’s a function of how “square” the weight hit the ground. This entire sequence was done by sliding the weight down a section of pvc pipe so that it would hit square.being smaller than the hole in the weight, there was some slop in how well the weight stayed in alignment.

  11. OT: Can they really be that stupid? (press)

    I’m watching the Australian PM make his announcement about the detection of possible debris from the flight being spotted by satellite in the southern search area. On the whole, I was quite impressed by his demeanor and reluctance at drawing any conclusions despite the harping of the press for him to do so. His AGO representative added to the statement as needed (when deferred to by the PM), and in passing he noted that the Search aircraft had a 4 hour transit and a 2 hour on station time to look for info that would verify what it was that the satellites spotted. The press puke then asks how long the aircraft can search. The AGO representative then had to restate what he had just said… because the press moron obviously didn’t comprehend what had just been stated to him.

    Check the idiocy: “Australia PM says debris found in South Indian Ocean likely from MH370” No, he didn’t say that. He said it could be from it… he also indicated that it could just as likely not be related. It’s just something that needs to be checked out and they are diverting/tasking assets to go look at it to see if it is from MH370.

    (Well, it’s HuffPo regurgitation of a Business-Standard article. Due to their shoddy work I am not linking to it.) has a much more accurate rendition of it.

    Satellites spot possible Malaysia Airlines plane debris off Australia

    See the difference? “Possible” They didn’t stick words in the PM’s mouth or misrepresent what he said. He said it’s worth looking into, and that is what they are doing.

  12. OT

    In an unfortunate display of double-sided domestic abuse, a man was arrested for assaulting his wife by locking her in the couple’s backyard shed.

    The man, 42-year-old Andrew Salmon, admitted to police that he had attacked his wife Beverley at their home in Truro, England, UK. The fight began after Beverly mocked the death of her husband’s mother with a Wizard of Oz reference by repeatedly chanting “Ding dong, the witch is dead.

    According to the Daily Mail, Andrew Salmon reacted by punching his wife, twisting her breasts, and ultimately locking her in an outdoor garden shed. Beverly managed to climb out the window of the shed and make her way back into the house, where the fight continued.

    Well, I can see where he would be justifiably upset… but I’m not so sure that the details of the assault were warranted.

  13. Truro is in the County of Cornwall. My sister lives there in a place called Grumbla . Cornwall is the The pointy bit at the South west end of England. The county is virtually cut off from the rest of England by the River Tamar. Anyone who lives the other side of the river is deemed a Furriner (Foreigner) By the Cornish people. They have their own language that nobody else wants to speak or understand and the place is overrun by piskies, little people distantly related to the Irish leprechaun and emmets (Ants or a derogatory reference to holiday makers who invade the county every summer). They eat Pasties, a torpedo shaped pastry filled with meat, carrots, swede and potato. They are also known to eat Stargazey pie. A pie made from various ingredients including whole fish baked in the pastry crust with their heads sticking out, their hapless eyes gazing upwards. Below some strange happenings in the fishing town of Mousehole. (pronounced Moosle) to remember a man who saved the town from starvation by catching seven sorts of fish.
    Since you have never visited us here in England Lurking this may encourage you to come on over………or maybe not 😀 😀

  14. A little bird told me Carl has a fever and is feeling miserable. Here is a little song that will cheer him up. 🙂
    (A ps to the dragons. Don’t go near him until all signs of the fever have gone and to make sure he hasn’t got the plague)

  15. Since this question was overlooked and I am really curious: I know it is possible with SWIR satellite imagery, but is there an image processing method to distinguish weather clouds from ash clouds on a webcam screenshot?

  16. Completely OT aftenoon rumination…

    I had a cup of coffee with a friend with a really odd job. He is out touring Sweden trying to solve a problem for Gällivare Town (population 8 500).
    Problem? Well, it is unemployment. But not the normal problem.
    His job is trying to recruit 3 500 people. Yes, the city has a negative unemployment equal to the entire workforce that has finnished school but not yet retired. Ie, -50 percent unemployment. In an attempt to get people to move there they offer salaries way beyond Swedish average and flying in and out is free of charge (there is also a train going several times a day). Downside is that this is really one of the last frontier towns to Europes largest wilderness.
    The nearby towns are not much better off. The economy up there is about as hot as the climate is cold. How hot is the economy in the regon? Well, think Greece, but in reverse.

  17. Hekla rumination!

    The news have lately been filled with dire warnings on Hekla being close to erupting. For some bizarre reason they claim that the northern part of Hekla is bulging when the GPS-record shows no sign of that happening. The media claims Páll Einarsson as the source behind this factoid.
    Here is a sign that should make people cautious, Páll is probably the most misquoted volcanologist in history. His misfortunate phrasings started the “Katla will blow” craze as he in one of volcanologys more weirdly phrased sentences claimed that Eyjafjallajökull and Katla always erupted close together. Only problem with that is that it is not true, nor has anyone ever seen the claimed magmatic connection between them.

    But, I do agree that Hekla is close to an eruption (whatever now that may mean) but that is based on current seismic activity and long time period GPS. In reallity Hekla is suffering from two very very slow earthquake swarms. One based at the southern end of the fissure swarm (might be pointing to a fissure eruption) and one near Hekla volcano itself.

    So, what about that inflation north of Hekla? Well, after a tremendous detective work I actually found an inflative period at Heklas northern end, to be exact it happened under Búrfell Mountain between 2006 and 2008. It was believed to be a series of small sill-intrusions from Heklas magma reservoir and it happened at around 4km depth. No further inflation has occured in the region, all later signals have been temporary in nature and are naturally occuring around a large volcano.

    As far as I have been able to gleen information out of the pertinent Icelandic authorities some of the earthquakes lately have had magmatic signals indicating rising pressure in the magma stack under Hekla. Those seismic signals have occured both under Hekla herself and out at the southern end of the fissure. This is probably the reason for the heightened alert-level and not any non-existing bulging. It is also probably the reason that Almannavarnir is working with a multiple scenario model for a future eruption.

    I should also state that the future eruption at Hekla at any given time is somewhere between 1 hour from now to a few decades away. Sorry, nobody can be more exact than that in prognosticating an unpredictable volcano like Hekla. In reallity we will not be sure that Hekla will erupt untill we see the telltale drastic drop at Búrfell. And it will not be a drop that you might say “Wonder what that drop is?”, it will be a drop you say “Oh crap” about. And once again, a Hekla eruption does not start with a few whisps of smoke.

  18. OMG, what did they do to Hekla’s webcam? It was always so pretty and now its a speck on the horizon. Oh and thats Burfell on the left.

    • It has been zoomed out. Most likely to better show the speed of a rising ash column.
      The advantage is that now we can watch horses horsing about on the farm.

      • Camara is zoomed cause they expect area can be from Búrfell and Bjólfell, to past Vatnafjöll
        (and this covers that).

        • And that translates to “anywhere along the fissure” and ove to the next volcano over Vatnafjöll. If Búrfell erupted it would be a surprise.

  19. Good to see you writing articles for VC Dr Webley! Especially when you so eloquently explain the capabilities and limitations of webcams. More please!

  20. Good news for the 2012 doomers. After all they were actually correct, there was a massive solar storm similar to the one in 1859 (Carrington event) in the year 2012. It was on the far side of the sun!

    It has been published now in Nature a study that confirms that a solar event on 23th July 2012 that had sparked an extremely fast solar wind, was actually a colossal solar storm, the kind of once in a millenium, and we were totally lucky. It happened on the other side of the sun. Had it hit the Earth things that year would have been so different. The impact was estimated to have been a disaster way more costly than that of Katrina.

    I can’t stop wondering. We are totally unprepared. Everyone.
    Imagine our power grids, mobile phone communications, GPS, airplane communications, internet, and even the possibility of currents induced in the power grids setting them on fire!

    News today on

    • Even if it had hit nothing much would have happened. This is one of the most overrated dangers ever deviced by an overheated brain.
      We did a lot of studies about it at Vattenfall and could in the end decide that only at a low-voltage over-used electrical powergrid could it ever be an issue.
      And the satelites are hardened so they will just be inaccessible during the event, and as soon as the event is over you can reconnect to them.
      This is just a media hype. I would be more worried about a lightning strike.

      • Nobody was killed by the Carrington event. That is just another media hype.
        The same goes for the highly publicized Quebec case of 1989. The electrical grid in question was highly over-used and was a low voltage system. Basically it had been going on a brown-out for more than a week allready when the solar-storm hit. Note that the largest solar-storm since the Carrington event could only disable 1 (ONE) transformer that was over-taxed on the entire planet.
        At Vattenfall (who owns and operates a 50 billion EURO network) we spent a lot of money on research into this in a 20 year long run of tests and came to the conclusion that no network run safely would suffer anything at levels equal to five Carrington events.
        The Quebec network was in 1989 the second oldest running network in the world with many parts not changed out since the late 1890s and early 1900s. And people are surprised it was pushed over the limit? And to continue. The same powergrid suffered another 3 transformer failures during the year leading up to the 1989 solar storm. But nobody ever tells that part since it is not “doomsday-sexy”.

        Brown-out is when the power grid is delivering less current than is needed, basically your 230 or 115 Volt system is running at a maximum of ten percent less (210 or 105 Volts), below that level the risk increases dramatically for fires to start. Next stage for a power company is to do a running denial of service (cutting power) with a districts being out of power for 4 hours at a turn.
        In Quebecs case the brownout was caused by an old transformer giving up the week prior to the solar storm and if that transformer had been online most likely nothing would have happened. But, saying that is not doomsday-sexy.

        Next tidbit, the Vattenfall network was hit harder than any of the North American networks during the 1989 solar storm. No effect on electricity services to customers was noticed, no component failed due to the storm.

        • Well, that’s a unique perspective… and in my book, quite welcome.

          The US had a recent blackout due to a tree branch on a poorly monitored line and suffered a cascade event. I have since theorized that the reason it did not make it down here to the coast was due to the fact that much of our distribution system here is periodically replaced because of tropical storm damage. This naturally induced revamping of the South East’s grid and distribution system has left us a bit more resilient to cascade failures. Just a pet theory, but your post supports that idea. 😀

          • I would put my money on you being accurate on that one. Basically, the more modern and upgraded your powergrid is, the less likely it is to fail for whatever be the reason.

        • Oh… and that “No one was killed by…”

          That doesn’t mean it can’t happen. Over my career I’ve been hit enough times to confidently state that some of the greatest injury comes from trying to get away from it. Whacked the back of my head really good when tying into the gyro signal for a repeater I was hanging over my equipment stack. The gyro signal ran at 400 hertz and feels completely different than 60 cycle. At the time I was kneeling over the terminal box under the deck plates and the status boards were directly above me. Those status boards were something unto themselves. You had to become adept at writing backwards on the plexiglass with a grease pencil, and cigarette ash on a napkin made the best eraser that you could get. (At the time, smoking was allowed.) The gyro readout was an addition that we made to our space since the original gear never had it’s gyro input wired in and the technical wizards who controlled all depot level maintenance would not let us hook the signal into the system. Our solution? Hand a repeater from the overhead so that we could look up and see the ships heading so we could make steering recommendations for chaff firing. My zap was not as bad as a friend of mine got. He was aligning a SPA-10 display and was leaned over into the cabinet, but kept getting bumped into and getting minor zaps when he brushed up against a terminal board. He got pissed off and the next guy that bumped him, he reached over and grabbed the guys arm, then grabbed plate voltage with the other. (roughly 300 to 450 VDC) Knocked the shit out of both of them. It wasn’t until afterwards that he found out that the last guy that had bumped him was the Watch Officer.

          “Wheels” didn’t really give a shit by then. He was just tired of them crowding him while he worked.

          • Back when I was ten I was very interested in radios, the old style with tubes in them. I did a lot of alterations to them to increase reception, one of the whackier ideas I figured out actually worked so well that I started studying physics to figure out how the hell it actually functioned. To this day I still haven’t figured out how it works. It is bugging my to no end that I as a ten year old discovered something that would most likely give me a Nobel price if I was not to stupid to figure it out.
            Anyhows. My other big discovery was that it is a very very bad idea to stick a screwdriver into the business end of a transformer of a set that is running. After that I have been extremely carefull around electricity. I guess I proved the old saying “burnt kids do not forget”.

            At eleven I discovered that crystal radios work partially by quantum pairing, something that actually was not proven untill last year. At 12 I discovered girls and got sidetracked for a good long time, I also discovered that building a volcano out of homemade gunpowder and napalm did not make girls interested in me. I guess I have not changed a lot over the years.

            • Wheel’s LPO wasn’t much better. He lugged his 10 meter amplifier into the shop and was tweaking it for a slightly different freq range. Idiot reached over to squeeze the output coil whit the thing up and running. He to found plate voltage and went hopping across the shop shaking his hand and cursing. From then on we called him Shakey Jake.

              Just to prove that they weren’t the only absent minded people, I had a “foot warmer” on my CB and was down on the fishing pier with my stepson. My CW key was about 250 watts, well above the legal maximum. I told my stepson to quit dicking with my car’s antenna because if he shorted it to the chasis, the SWR would skyrocket and I would get a lot of reflected power back into my amplifier, potentially killing it in a rapid manner, burning out the finals. Well, he reached over and grabbed it while I was on key and drew a nice half inch spark into the tip of his finger. He listens to me know. (He had grabbed a voltage high on the antenna)

  21. Dayli “Daily Fail” article. Is there any news in this article? This seems be failed attempt at Volcano Doom (as in doomsday mongering), but is too vague, no real story in it.
    Why Laki and other “larger volcnos” suddenly fell into the plot is mystery…
    “supposably Hekla be lead actor in todays” story.

    As Carl says abowe, we both expect Hekla can (will) erupt (relative) soon 😉
    but possibly with other variation than most talked about.

    • Urgh… that was a low point in faulty facts, even for The Daily Fail. I am not going to read that book, ever.

  22. Quake in Vatnafjoll.
    20.03.2014 21:29:11 63.952 -19.638 9.1 km 1.2 99.0 4.7 km SSE of Hekla

    • Yes, Vatnafjöll as close as it gets.
      Say, it would be surprise to have Hekla blow out there (why not?)

      • If it blows out there I would say it is Vatnafjöll, and I am fairly certain that the lava would be Vatnafjöll lava (baseline basalt) and not Heklas odd lava.

    • Yepp, not Hekla related.
      But two interesting Vatnajökull quakes running from Thordharhyrna to Hámarinn. There is a known connection between those two, and the depths at 12 and 18 km are intriguing.

    • And since it is Friday.
      Have you ever wanted to find your inner Finn now when it is bad times around the world again?
      Now you can become a Finn!

      Becoming a Finn will give you these advantages.
      You will automatically strike with a bonus dice, if you are striking a Russian you get two bonus dices.
      If you are equiped with a Knife of Despair you get a bonus 10 in damage against normal opponents and a bonus 50 against Russian players.
      If you are equiped with a bottle of Water of Life (Vodka) you heal twice as fast as a normal mortal.
      If you invest in a Dungeon of Sauna you become impervious to both cold and heat. Finn, a good character to play in a world gone bad.

      • You have to hand it to the Finns, they had/have a very practical pantheon.

        TUULIKKI Goddess of the Woods.

        Daughter of TAPIO and MIELIKKI, she makes sure the woods are well-stocked with edible creatures.

        In a modern adaptation, would she be considered the goddess of the pantry? I’m always quite happy when I go rummaging around in there and find something nice to eat.

  23. Before the Riddles and the normal Friday post comes online, here is something to keep you in a good mood.
    No points, but it will nimble up your work tired brain.
    What is this? And what volcano is it?
    Image and video hosting by TinyPic

    • And it seems to be hat and dance in the future for me… Very interesting depth.
      Friday 21.03.2014 13:23:39 63.636 -19.052 27.6 km 1.3 99.0 6.6 km NNE of Hábunga

    • It was a trick question.
      It is actually the Chillean quake on the 17th.
      It is surprisingly hard to separate a tornillo from a volcano and a teleseism from a large earthquake as the planet has filtered away the initial break component.

        • Yepp, it is a bit on the low side.
          But, in this case I had to check against the global earthquake list to make sure after spotting that the frequency was below what a conduit can physically produce.
          A conduit or a chamber must be wide enough to actually be able to carry and create a wave that is so big. Remember that a wave increases in size as the frequency goes down.

  24. Yet another Hekla quake
    21.03.2014 12:47:32 64.004 -19.604 7.1 km 1.2 99.0 3.4 km ENE of Hekla

  25. I have to run a couple of errands, so the riddles will be a tad late. But not that much since the post (minus riddles) are ready to go.

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