Tambora: 200 year Anniversary of the 1815 eruption

April 2015 will mark the 200 year anniversary of the largest recorded eruption in historic times. Yes, Tambora.

Tambora’s sulphate dust clouds are now attributed with disrupting major weather systems for more than three years, causing net global cooling, global crop failures in 1816, famine and disease, including a cholera pandemic. Yet, despite being one the largest observed eruption in recorded history, at the time it passed relatively unnoticed outside the region. In Europe, Napoleon had returned to power in March 1815; and, armies were being mobilised to defeat him. Sir Stamford Raffles, the British governor of the region based in Batavia, was in the process of building a local system of free-trade. However, eye witness accounts from trading vessels off the cost of Sumbawa and resident administrators obtained by Raffles have survived.

The Eruption

On 10 April 1815, an eruption with an estimated size of VEI-7 destroyed the summit of Tambora, removing the top third of the edifice, leaving a 6 to 7km in diameter, 600 to 700m deep caldera. The immediate death toll on the island of Sumbawa is estimated at around 10,000 to 11,000 people from the eruption, itself, with a further 60,000 to 110,000 in the region from starvation or disease. An administrator sent to investigate the earlier 5 April 1815 eruption was among the first victims.

Fig 1 Caldera_Mt_Tambora_Sumbawa_Indonesia

Fig 1: Mount Tambora. Image by Jialiang Gao (peace-on-earth.org). Published under Creative Commons Attribution-Share Alike 3.0 Unported license. http://commons.wikimedia.org/wiki/File:Caldera_Mt_Tambora_Sumbawa_Indonesia.jpg

Before the April 1815 eruption, Tambora had been dormant for over a thousand years, awakening in 1812. She was between 4,000m and 4,300m high and clearly visible from Bali. On 5 April 1815, she erupted with what is described by local witnesses as a loud thunderclap, tremors and huge plumes of flames – the first of two plinian eruptions. This settled down after a few hours and, from then to 10 April, there were smaller emissions. At around 19:00 hrs on 10 April 1815 the main eruption started – the second plinian eruption. It is described as three merging columns of flames, a flowing mass of liquid fire, heavy pumice and ash fall, and pyroclastic flows. The eruption lasted approximately two days. The ash cloud reached west Java, southern Borneo and south Sulawesi. Villages on the north, west, south and east slopes of the volcano were destroyed by pyroclastic flows and lava. A 4m high tsunami caused by pyroclastic material entering the sea devastated the Sanggar coast. Between 95 and 175 km3 of tephra (30-33km3 DRE) are estimated to have been erupted.

Analysis of the deposits show that the eruption occurred in two phases: the first phase was at least four tephra fall episodes; and, the second comprised at least seven pyroclastic flows. It is during the second phase that the summit is believed to have collapsed and the caldera created.

So what caused the eruption?

Tambora is an active shield like alkaline volcano located on the Sanggar Peninsular on Sumbawa Island, Indonesia, in the eastern sector of the Sunda arc. Volcanic activity on Sumbawa have occurred from the early Miocene through to the Holocene. Tambora, herself, is younger than 200 ka, overlying the 410ka Kawinda Toi volcano.

Tambora is not Indonesia’s most active volcano. GVP lists only seven confirmed eruptions in the Holocene: 3910 BCE ± 200 yrs, 3050 BCE ?, 740 ± 150 yrs, 1812 to 1815 VEI-7, 1819 VEI-2, 1880 ± 30 yrs VEI-2, and 1967 ± 20 yrs VEI-0.

Fig 2 Sumbawa island

Fig 2: Sumbawa Island, Indonesia from Google Satellite.

Tambora is located 340km north of the Sunda Trench at the back of the main volcanic arc 180 to 190 km above the Benioff Zone. The crust is young and between 14 to 17 km thick. The upper part of the crust is made up of Cenozoic siliciclastic marine sediments and limestones with volcanic and intrusive rock. Here Indo-Australian Plate subducts beneath the Sunda Plate. To the east, the subducting plate changes nature from oceanic to continental. Back arc thrusting has been reported from Bali to Flores Islands.

Fig 3-Sunda_Plate_map-fr

Fig 3: Sunda Plate. Image by Sting and Rémih, published under Creative Commons Attribution-Share Alike 2.5 Generic license. http://upload.wikimedia.org/wikipedia/commons/e/e6/Sunda_Plate_map-fr.png

Looking at the latest 5,000 earthquakes published by IRIS for the area between Bali and the western end of East Nusa Tenggara we can clearly see the subduction zone:

Fig 4 tambora yz

Fig 4: Subduction zone. Copyright rests with the author. Reproduced here with her kind permission.

Tambora’s lavas are potassic, silica-under saturated lavas and pyroclastic rock ranging from nepheline-normative alkali basalt to trachyandesite. Her lavas are consistent with other Sunda arc quaternary volcanoes: Muriah, Ringgit Beser, Sangeang Api and Batu Tara.

The rocks now exposed in the caldera wall show four pre 1815 volcanic formations. Lava flows of 43ka which fill an earlier caldera, which are overlain by the Black Sands pyroclastic unit and the Brown Tuff formation. Radio-carbon dating of the Brown Tuff formation indicated that it formed between 5900 and 1210 14C years BP. This was the last known activity before the 1815 eruption. Check out the photos in Tambora’s caldera for an idea of the strata (not reproduced here as copyright is not certain).   The lavas of the 1815 eruption were almost exclusively trachyandesite (latite) – tephriphonolite, which is relatively rare in volcanic arc settings. They are believed to be some of the most evolved products of the volcano.

Cooling of a hydrous magma in the magma chamber led to the exsolution of fluid magma and crystallisation of the magma during the period of dormancy. Overpressure in the magma chamber led to the eruption. The mechanics of the eruption were similar to that seen more recently in the VEI-6 eruption of Pinatubo in June 1991. SiO2-undersaturated potassic trachybasalt formed from the partial melting of a garnet-free I-MORB like mantle source fluxed with fluid from the subducting slab and small amounts of subducting sedimentary material. This trachybasalt differentiated to trachyandesite in two stages: around the Moho at 14 -17 km; and, in and a shallow crustal reservoir at 2 to 3 km. In a deep magma reservoir near the Moho, aluminium oxide rich trachybasalt and basaltic trachyandesite evolved from the mantle sourced aluminium oxide poor trachybasalt. In the shallow crustal reservoir, trachyandesite and phonolite evolved from the aluminium oxide rich basaltic trachyandesite.

Fig 5 -Pinatubo91eruption_clark_air_base

Fig 5: 12 June 1991 eruption of Pinatubo (three days before the climactic eruption). Image by Richard P. Hoblitt, USGS, http://www.usgs.gov/

Fig 6 TAM_NE-Gas-4966

Fig 6: Gas emissions on the caldera floor of Tambora. Image by Georesearch_Volcanedo_Germany, published under Creative Commons Attribution-Share Alike 3.0 Unported license. http://upload.wikimedia.org/wikipedia/commons/e/e5/TAM_NE-Gas-4966.jpg

Hope you enjoyed reading this. The usual caveats apply “not an expert, etc.”

KarenZ, March 2015.


  1. Wikipedia: http://en.wikipedia.org/wiki/Mount_Tambora ,
  2. Wikipedia: http://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora ,
  3. GVP: http://www.volcano.si.edu/volcano.cfm?vn=264040 ,
  4. IRIS: http://ds.iris.edu/ieb
  5. Igan Supriatman Sutawidjaja, Haraldur Sigurdsson, Lewis Abrams, “Characterization of volcanic deposits and geoarchaeological studies from the 1815 eruption of Tambora volcano”, Indonesian Journal on Geoscience Volume 1 Number 1 2006: 49 – 57 http://jgi.bgl.esdm.go.id/index.php/IJOG/article/view/8
  6. Ralf Gertisser, Stephen Self, Louise E. Thomas, Heather K. Handley, Peter Van Calsteren, and John A. Wolff, “Process and timescales of magma genesis and differentiation leading to the great Tambora Eruption in 1815”, Journal of Petrology Volume 53 Number 2 2012: 271 – 297 http://petrology.oxfordjournals.org/content/53/2/271.short
  7. Gillen D’Arcy Wood, “Tambora: The Eruption That Changed the World”, Princeton, NJ: Princeton University Press, 2014. ISBN 978-0-691-15054-3
  8. Clive Oppenheimer, “Eruptions That Shook the World”, Cambridge: Cambridge University Press, 2011. ISBN 978-0-521-64112-8

95 thoughts on “Tambora: 200 year Anniversary of the 1815 eruption

  1. Lost Kingdom” Discovered on Volcanic Island in Indonesia

    “The eruption of the volcano Tambora in 1815 killed 117,000 people in Southeast Asia, including those believed buried under ten feet (three meters) of pumice and ash in the recently discovered village.”

    Tambora Caldera E-W profile from Google Earth path elevation function.

  2. Thank you so much Karen Z . You may not be “expert” but this is one very fine piece of research giving lots of information in a very concise post.
    Certainly you have demonstrated the very complex nature of the geology of this volcanic area.
    If you are an “administrator” sent to inspect an erupting Volcano, do take all precautions to stay as far away as possible and read VC and other volcano blogs for updates and info before setting out. Leave closer inspection to the professionals
    Of course the problem is nobody can predict what a volcano has hidden in it’s innards, but these days luckily, the professionals can provide surprisingly accurate informed guesses.

  3. Well, despite the fact that “supervolcano” is a media construct intended to sell eyeballs, there are several volcanoes in Indonesia that are catastrophically explosive in their historical nature.

  4. Thank you so much for this reminder KarenZ, it’s a great article – Tambora should give us all food for thought. I was going to write a short article on the aftermath of this eruption. Would VolcanoCafe be interested?

    Meanwhile, there’s been a tiny, tiny drop at Hekla – around 3 or 4 this morning. Just to remind us all she’s still there I guess! 🙂

  5. It hits you in the head if you aren’t aware of big anniversaries like this. 100,000+ people

    Hekla, a clump of them.

    • Just a note to say that I’m still lurking after a holiday to NZ, nothing erupted….
      I expect there are lots of lurkers, just less to say these days.
      For the moment anyway.

  6. Today’s date back in 1964 was the 9.2 earthquake in Alaska. Here’s an article from Earth Sky about it. It’s known as the biggest earthquake in North America.


    I haven’t read Tambora article yet. I’m making a hot cup of tea to drink, then I’ll sit and enjoy the article. 🙂

    • Good post, KarenZ. Such a huge loss of life. To think of the things that happened and then I see ‘the second phase had at least seven pyroclastic flows’ WOW.

    • That 9.2 in Alaska generated MMI XII shaking out to around 29 km from the epicenter. MMI XII is the level in which stuff is literally thrown up into the air with over 772.5 %g peak ground acceleration.

      • The shaking went on for 4 minutes according to the Earth Sky article 😮 Amazingly the death toll was only 130. Perhaps people were out of doors as it was a warm day.

  7. You know, I just KNEW somebody would have to post on Tambora – great post, Karen. Odd fact department: Tambora 1815 and Novarupta 1912 have one peculiar thing in common – in both cases the first scientific expedition to reach the eruption site would be led by a botanist: Heinrich Zollinger (1847) and Robert Griggs (1916) respectively.

    • Us Biologists have our uses :D….. The Botanists tend to elbow their way in first and have an easy time as plants tend to stay put. Zoologists have a more difficult time as their quarries tend to either hide , run away or worse….attack. 😀

      • Lurking do stop shoving me…I may be a biologist but I am not…Repeat NOT.. going to climb Hekla to check on her status.

        • I’m not pushing…. yet.

          The only person that I would actually “send” to the top of Hekla… would be a bureaucrat and fully deserve to be placed in such a dangerous location.

          (Hekla gives almost no warning when it erupts… and what warning it gives is only discernible by instrumentation. In Hekla 2000, the quakes only reached the level of human perception about 15 minutes prior to showtime.)

  8. Panama City Beach church loses tax exemption after opening club

    A local church that has been hosting naked paint parties and slumber-party Sundays with the “sexiest ladies on the beach” will now have to pay taxes on the property as officers investigate the church’s practices, authorities said Tuesday.

    The Life Center: A Spiritual Community, 9721 Thomas Drive, has been up and running its seven-days-a-week party schedule as Amesia: The Tabernacle since Feb. 28. But The Tabernacle, which caters to college students on vacation, has caught the attention of more than just party-seeking spring breakers.

    Since ATMs and a banner promoting “iDrink” appeared out front of The Life Center, the Bay County Sheriff’s Office and Panama City Beach Police Department investigators have began taking a closer look at the church. Owned by Markus Q. Bishop, former pastor of Faith Christian Family Church, officials said the club has been engaging in activities unbefitting of a church.

    A sign on the front of The Tabernacle stated the events are alcohol and drug free and donations go back to the church. Promoters said it is a church by day and youth ministry by night.

    Since a Facebook post from BCSO questioned the integrity of the club, highlighting that the club often hosts adult entertainment, Club Amnesia has shut down its website. However, when the website was available, it boasted a Sunday night event called “Slumber,” a pajama and lingerie party hosted by “the sexiest ladies on the beach.” Raves take place weekly along with an “Anything But Clothes” paint party.


    30.177271°N – 85.798100°W 600 meters from the Beach.

    • Is this, 30.177271°N – 85.798100°W 600 meters from the Beach, for any of those pilots who may want to investigate the paint party? 🙂

    • Well, I tend to miss Panama City Beach from time to time on job tickets that I do. I have on occasion gone to Panama City and had to back-track across the city. Both sites fall under the same county authority. On one trip through Panama City to get there, I ran across what seemed to me like a huge latex spill, based on the distinct aroma. Either that or someone was having one hell of a latex party.

      Both locations are just plain weird… during Spring Break. Less so at other times. Probably the most entertaining bit of local news heard on the radio was that Parker Florida had to have a special election in order to replace the city council person that was arrested buying krank in a parking lot. I didn’t know that “crystal meth” was so important to city council meetings.

      The other reason for posting it is that some readers here like to sight see via Google Earth.

    • And I spotted this the other day. When it comes to selecting a good site for your business, it’s all about location, location, location.

      30.480037°N – 87.216943°W Looking south.

      • Goodness..Right next door to Staples…….. Dunkin Donuts hasn’t managed to get much of a foot or should I say Teeth Hold here, but we do have Staples . When I worked for Iron Mountain they were right next door to us. Very useful when we ran out of office supplies. 😀 😀 This was my last job before retirement. NW regional IT Trainer/Quality Control and health and Safety……I quite enjoyed it . It was different. 🙂

      • Today I was doing work the next county over and had a couple of hours to kill. In Florida, if you let your insurance coverage lapse, your tag gets revoked. Right next door to the tag office, is an insurance company.

        The Google street view imagery is blurred so no pic.

    • Abandon Hope all Ye who enter here.

      Another photo I found on the beach was labelled ” Redneck Riviera” . You have a Class system in the USA? Anyways away from political sociology, we have a similar resort here in the UK . Blackpool. developed at the end of the 19 Century to create a playground for the thousands of Mill workers in the North West of England. It too has similar establishments as Ripleys, a Pleasure beach with fair ground rides and the scary “Big Dipper” a fore runner of the Theme Parks of today. It is now very seedy and run down. A very sad place. I think in time it will be restored and the whole town will become a museum piece of the British Holiday Industry. Funnily enough only a couple of miles further along the coast, same sandy beach, is the resort of Ltham St Annes. . for those who may feel they don’t wish to mix with the hoi polloi yet secretly sneak into the Pleasure beach for a quick thrill. 😀

      • “Redneck Riviera” is a pretty common colloquialism for the entire gulf coast around here. Another one they like to use is “Emerald Coast” due to the green. Not for any particular Irish connection, though Ireland provided a lot of ancestral stock for the people that settled in the Deep South. “Redneck” itself is sort of an intended disparaging label, but many of us who are “redneck” take great pride in the heritage. Fact of the matter, comedian Jeff Foxworthy made probably the best description of redneck that I have ever heard. “A glorious lack of sophistication,” which essentially means that pretty much anyone or nationality, can and do have rednecks in their population.

        You might be a redneck.

        Warning, do not EVER try this. It takes a group of pretty much certifiable idiots to do this.
        This is one of the reasons for the running jokes about usually the last thing that a redneck says before dying is: “Hold my beer” or “Watch this”.

        From the surrounding vehicles in the background, this appears to have been at a mud bog event. The idea is that aficionados gather together for the express purpose of driving through mud. In my experience, though they are built up for such activity, these offroad vehicles cannot hold a candle to some of the monster vehicles that Icelanders are known to put together.

        Side note: I literally lost my license at a traffic stop near an event like this in Mississippi. After taking my license and checking my registration, the officer gave me back the wrong license. I didn’t find this out until I got to my destination and I had to make lots of phone calls the next day. When I picked up my license at the county courthouse where the officer dropped it off at for me, it came with a traffic citation for no registration. That took additional phone calls and the officer had to come back in from patrol to resolve it. (my registration was valid). He tore up the citation and sent the other guys license back to him in the mail. So, some 18 year old kid had to explain to his dad that the highway patrol took his license, and endure the family discourse around that, only to have it show up in the mail in a couple of days with no citation or explanation. I have long wondered how that turned out.

        • Dunno how they fit into the grande scheme of things, but I know that by 1790, one of my ancestors were party to a court case in Natchez MS and were awarded damages in the form of “10 gallons of good whiskey” and a string of horses the worth being determined by a court appointed representative. You can’t get much more Irish in lineage than Sullivan.

      • ” You have a Class system in the USA?”

        Only by those pompous idiots that wish to place themselves above others. I ran across one on the phone the other day who was ticked off that I had not contacted the server management desk after a PM that I had done. [expletive deleted] was so full of himself that I sort of wished to do bodily harm to him. He was completely dumbfounded when I informed him that I did call the server desk but none of his people answered the phone. His response was that I should have gotten the main desk to send the after hours representative an Email so that he could call me. “If no one answers the phone, how do I do that?” → more fluffery. Truthfully, this sort of smarmy B/S is one of the main reasons that got out of the military. Though I don’t have proof, I have a really strong impression that the royal cluster#$%# that will happen statewide on Monday is due to this moron’s poor planning and self aggrandizement.

  9. Swarm of deep quakes where the dike turned left.
    28.03.2015 13:39:53 64.592 -17.172 15.0 km 0.8 99.0 17.7 km ESE of Bárðarbunga
    28.03.2015 13:39:38 64.599 -17.189 19.1 km 0.8 99.0 16.8 km ESE of Bárðarbunga
    28.03.2015 13:37:31 64.593 -17.189 14.7 km 0.8 99.0 17.0 km ESE of Bárðarbunga
    28.03.2015 13:37:15 64.603 -17.224 21.1 km 0.6 99.0 15.1 km ESE of Bárðarbunga
    28.03.2015 13:36:57 64.595 -17.200 13.0 km 0.7 99.0 16.4 km ESE of Bárðarbunga
    28.03.2015 13:36:49 64.600 -17.205 20.1 km 0.8 99.0 16.0 km ESE of Bárðarbunga
    28.03.2015 13:32:07 64.663 -17.578 7.8 km 1.8 99.0 3.5 km NW of Bárðarbunga

  10. Like
    The deep quakes aren’t just going on there. But also way southeast where that tall stratto volcano Oreafajokull has been having deep quakes of 20+km deep. This includes a 1.1mag 25m depth

    GL Edit: Requested changes made.

  11. Dunno about you, but I feel that a hospital that has an artistic rendering in the lobby of something that seems to be based off of a biohazard symbol to be a bit creepy. → ☣

  12. Heads-up for Sakurajima everyone.

    Average 450 eruptions a year. So far in 2015, over 300 eruptions.

    31 eruptions on March 27th alone. I’ve been watching the webcam:


    Deformation/swelling has been reported, and the alert level was raised from 2 to 3 on March 24th – “Do not approach the volcano”.

    This is potentially shaping up to be something biggish. Raw data (in Japanese) from JMA: http://www.data.jma.go.jp/svd/vois/data/tokyo/STOCK/volinfo/gensho.html

    (This report from my own observations and from a contact in Japan)

  13. Thank you, Karen, for a nice and timely article. How little we know about how the eruption started.

    If you look at the list of volcanoes perceived as ‘most dangerous’, volcanoes like Tambora or Krakatoa tend not to be on it. Instead they mainly list ones which have a reputation of erupting often. Sakurajima is often listed, as are Merapi and Vesuvius. But the most devastating eruptions have in many cases come from volcanoes which had been quiet for a long time. Which ones are the real dangers? Pinatubo was recognized in time and handled very well locally. Can we be confident that the next big one will not come as a surprise?

      • All volcanoes worth watching (and staying away from). But the lesson from your article is that we should be aware of volcanoes that have no recent history of large eruptions and seem to have gone to sleep.

        • Tambora gave three years warning. Today with more knowledge, we may have put monitoring in place that would have reduced the immediate death toll. A global famine and cholera or other pandemic would be more of a challenge.

          I guess that if a volcano in a location that was difficult to monitor woke up, mitigation would be more difficult. Difficult to monitor could be due to remoteness or lack of investment in monitoring equipment.

          But don’t forget, I am not an expert.

          • Glacier Peak is one of those. Seattle area is very close and it is capable of a St. Helens VE-4
            or even a VE-5….

            • Glacier peak is capable of more than a VEI-5, it had a series of VEI-6 eruptions in the geological past (I believe around 10k years ago), although I’m fairly sure you know about this already.

              Rainier still is public enemy #1 in terms of danger if for no other reason than potential lahars. With that said, one scenario that receives no mention is the potential for a scenario similar to St. Helens, where you get a slope failure resulting in a lateral blast. Cascade volcanoes have a history of slope failures – this is largely a product of their brittle construction, the presence of glacial activity weakening the edifice, and the overall size of the edifice itself. Given the prominence of Rainier and how altered the volcano likely is, I would easily list it as one of the top volcanoes in the world at risk of a slope failure provided an eruption or any type of dome growth activity. Also, Rainier has had slope failures in the last 10,000 years. The largest lahars that occurred came from a small slope failure around 6000 years back I believe.

      • Valid observation. Until Mt St Helens started showing signs of unrest it was pretty much ignored. Even after it gained the attention of the USGS, the ramifications of what it could do were not known. (RIP David A. Johnston and others)

        Here is a man happily immersed in his work. 13 hours later this area was overrun by a lateral blast.

          • One reason there is so much concern over Rainier is the possibility that a major slope failure could happen WITHOUT an eruption; perhaps triggered by a large nearby earthquake, or a spell of exceptional rain/snowfall. One of Rainier’s major Holocene debris flows (Electron?) doesn’t seem to have an associated eruption. And that sort of event might produce sod all in the way of warning signs

        • All very familiar to me. flew over and around-before and after- St. Helens blew
          out… After the eruption calmed down, the July 22 blast caught everyone off
          guard-again less than 24hrs, from tremors to blast.. At a girlfriend’s place in the pool when we looked to the west-and there was a nice Mushroom cloud.
          Her pop who worked at Los Alamos for a number of years, casually said:”Hmm.-reminds me of that last above ground shot at Yucca…”
          Next day we had a bigger mess in the Handford/TriCities area of Washington
          than we did on May 18 (1980)

  14. A long time ago in a place far far away… (Jersey), I would get up and drive to work. Typically my brain had not had time to assimilate the coffee by the time I was driving. Cranking up a CD would tend to have my brain working by the time I got to my destination. To me, it was a sort of zen thing. Of late, I have been having issues with actually dozing off in the evening. At 6:30 AM this morning, I got pissed off, got up and made breakfast. Satiated, and with coffee at hand, I finally dozed off. Now I’m trying to get my brain back online after waking up. So, here is what I’m using. Enjoy.

    Reportedly, that line of Japanese at the beginning translates as “What the hell are you saying, you senile old fart!” — appropriate 😀

    Why White Zombie? Well, my stepson’s first wife knew of my appreciation of hard rock and thought it cute to give me a CD of “La Sexorcisto: Devil Music, Vol. 1”. Initially, I didn’t have much appreciation of it since I was more of an Aerosmith/Led Zepplin fan. However, I grew accustomed to it and on loong weekend when I needed to perform some minor miracles with Perl CGI, I had my reference manuals, 4 liters of Mountain Dew at the ready, and this CD spinning all weekend long. It was probably one of the best coding sessions that I ever had, almost religious in it’s effect. I got the programs up and running on the server and was quite satisfied with my work. So, to this day, White Zombie has a special place in my head.

    I blame the ET shop on my first ship for turning me on to having hard rock blaring in the background while you are trying to solve a difficult problem with a piece of gear on the bench. It’s good to keep your mind focused and steers you into a mental rhythm.

    • Speaking of the ET shop. One of the funniest things that I saw them do was to pin a guy to the bulkhead using old SPS-10 magnetron magnets. Magnetrons are the item in a radar that generates the microwave energy pulses that are sent down range and then the reflections are picked up on hypersensitive receivers. Magnetrons use a “crossed field effect” where a very intense magnetic field causes the electrons coming off of the cathode to steer a tight orbit around the resonance chambers. If you are ever going to build a homebrew seismograph, a Magnetron Magnet can give you the ultra strong field that you need to generate a signal in your coil when it is vibrated.

  15. Other things happening in 1815, the Battle of New Orleans. Andrew Jackson, with the assistance of the pirate/privateer (depends on who was doing the asking) Jean Lafitte and his forces from Barataria.

    Barataria was where Lafitte and his brother had set up warehouses for moving goods that they had procured.

    Lafittes greatest contribution was in the form of artillery and expert cannoneers. Despite the traditional tales of the story, a lot of the actual blame can be made in the realm of not having the proper equipment to scale the earthworks following the British charge to the line. “Almost universal blame was attributed to Colonel Mullins” who was responsible for preparing the equipment. (Wikipedia’s version of it).

    Personally, I attribute the defeat as much to the quagmire that is the essence of a cypress swamp. Some pretty nasty stuff lives in those swamps. Moccasins, Gators… etc. Additionally, Britain had other issues to deal with and focused much of their effort on the Napoleonic Wars. This probably had as much to do with Britain giving up on taking New Orleans as anything else. Why they were intent on taking New Orleans to begin with is beyond me, we had bought the Louisiana Purchase from France for what amounted to approximately four cents per acre. To me, that is akin to someone’s ex wife seizing the car that you bought from the couple 12 years before they divorced.

      • These beach balls are all for the same quake (ESMC’s manual solution yellow star), just different focal mechanism solutions by the various seismological organizations. (black dots)

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