This is any device that is designed to cause some sort of seismic event. Usually, an earthquake.
Almost every Mad Scientist has at least one of these in his blueprint library, sometimes even two. Sometimes simply called the Earthquake Machine, or the Quicksand Generator, Liquefaction Array, or even Ruin Device. If it does the two things that all earthquake machines have in common, it will: 1) cause earthquakes as its primary function, 2) probably be a machine, although there are a few examples of this trope involving living creatures instead of machinery.
A modernized, although not necessarily more realistic take will probably depict such a machine as a Kill Sat or something along these lines. This is derived from conspiracy theories concerning HAARP, some of which accuse the project of producing earthquakes for whichever nefarious purpose the NWO might have for them at the moment.
Occasionally overlaps with This Is a Drill. While a Colony Drop might cause an earthquake, and might very well involve a machine, the earthquake is simply a by-product of, well, a dropping colony. Compare Weather-Control Machine, which can be used to create similar chaos in the atmosphere instead of on the ground.
- Bubblegum Crisis: Tokyo 2040 has one employed in its backstory as GENOM tried to keep runaway boomer technology from getting loose, deciding to employ the device to bury the lab, and causing the city to be rebuilt. However, this didn't destroy the technology as it later got loose.
- Lupin III
- Subverted in a Marvel one-shot about Hulk and Venom versus a Mad Scientist named Dr. Bad Vibes, who claims his machine is responsible for a string of earthquakes. When they track him to his lair... Bad Vibes is just a crazy old homeless man threatening them with a cardboard box with "Earthquake Machine" written on it.
- Batman: Robert Coleman is an architect of some note in Gotham City. His reputation is irreparably damaged when an apartment complex he designed and built does not withstand a hurricane. Feeling that he has been wrongly branded, Coleman creates the alias of the Quakemaster and uses his super-charged jackhammer to create earthquakes in Gotham City.
- Mortadelo y Filemón: In Desastre, a Mad Scientist threatens cities using several types of Doomsday Device, the last one causing earthquakes and threatening the heroes' own city.
- The absolute first appearance of Lex Luthor (then only known as Luthor) in The Golden Age of Comic Books Superman comics involved Luthor stealing one of these.
- The Thunderbirds spin-off comics had a story called "The Earthquake Maker" in which a Mad Scientist named Parthal used one of these to destroy four Iranian cities. These turned out to be simply tests in preparation for his main plan, which was to split the country in half from the Persian Gulf to the Caspian Sea, causing devastating floods. While monologuing about this, he explains that the government of Bereznik is paying him a fortune for it, although we never find out what their motive is.
- In The Big Bus, the villain wants to stop the eponymous transit vehicle from being able to make a non-stop trip from New York to Denver, so when it leaves the road and ends up on a cliff, his brother wants to use the earthquake machine to knock the bus over the cliff. When he aims the earthquake at his brother's location, in his iron lung Hilarity Ensues.
- In Conspiracy Theory, the conspiracy theorist protagonist stumbles upon a conspiracy to kill the American president through an artificially induced earthquake. The machine is not described, but it's apparently fired from aboard a space shuttle.
- The Deep Earth Seismic Trigger Initiative, or DESTINI, superweapon from The Core.
- In Ocean's Thirteen, the crew uses a tunnel drill to simulate an earthquake hitting Las Vegas (specifically the Bank casino) in order to get everyone out of the building (to prevent people from losing the money they just won). However, the building continues to shake even after the drill stops working. In a deleted scene, Roman Nagel suggests to Livingston Dell the possibility of the fake earthquake causing a real one.
- In Under Siege 2: Dark Territory, Casey Ryback has to deal with the bad guys who have got their hands on the controls for just such a Kill Sat. If that wasn't silly enough in itself, the villain uses its ability to produce "earthquakes" to shoot down a jetliner and several fighter planes in mid-air.
- Forest Kingdom: Rockbreaker, one of the three InfinityPlusOneSwords featured in book 1 (Blue Moon Rising), was one of these.
- The Russian children's novel Journey to the Morning Star has this as a Superweapon Surprise by the peaceful Etherians, who normally use ultrasonic waves to stop planetquakes. It takes a human to point out that they could just as easily cause a localized planetquake, making it a devastating weapon against the warlike Sinots (although, only when they're actually on the ground). They use it a total of one time before the Sinot population rises up against their oppressors and offers peace to the Etherians.
- In Macdonald Hall 's The War With Mr. Wizzle, Elmer conveniently has a minor earthquake machine built, which the guys sneak into Wizzle's home and then convince him the home is built on a minor faultline.
- In the Doctor Who story "The Enemy of the World", the eponymous dictator Salamander's evil scheme involves causing earthquakes in territories that oppose him.
- This causes the Undertaking in Arrow. Specifically, the first season's bad guy uses one or two, actually to destroy a particularly crime-ridden section of the city.
- Jimmy Kimmel Live! had a segment joking (among other items) about the "post-quake camouflage" bandanas found on a website selling "disaster"-themed goods, at which he questions why you'd want to blend in after an earthquake... unless you somehow "caused it" and wanted to get away. (By default, he assumes he'd want to be found.)
- Space 1889. Machines that can cause earthquakes or volcanic eruptions are possible inventions in the main book.
- In Assassin's Creed: Rogue, one appears in the form of a piece of Eden wich causes the Lisbon earthquake of 1755.
- In Battle Zone 1998, the NSDF Grizzly Hover Tank and its CCA counterpart carry the 'Thumper', a special weapon that channels biometal ammo directly into the ground to create a massive earthquake wave that will send enemies flying helplessly into the air.
- The Soviets in the Aftermath expansion of Command & Conquer: Red Alert have access to the M.A.D. Tank, a vehicle that uses a large piston to release a wide-reaching and highly damaging seismic shockwave. However, it has no effect on infantry and the M.A.D. Tank destroys itself in the process.
- Final Fantasy XIII Vanille's Limit Break counts as this, as a heroic example. Alexander also uses this as a special ability, via Ground Pound.
- In No More Heroes, this is Letz Shake's weapon of choice: a giant, silo-like device capable of unleashing a magnitude 20 seismic blast when fully charged (bear in mind, he's supposed to be an assassin). We never get to see it in action as the instant before it finally charges up, he and the device get slashed completely in half by Henry. It ends up coming back in No More Heroes 2: Desperate Struggle in the form of the newly-rebuilt Dr. Letz Shake, adapted into a smaller, but still devastating Spider Tank version of itself. This time, he actually is fought, and while his earthquakes are much smaller, they can still One-Hit Kill Travis if he stands in the wrong spot.
- PC mecha-sim game Starsiege had these in one mission on Mars. Known as 'Hammertanks' or 'Thumpers,' these were modified drilling platforms designed to shake HERCs right off their feet. Seeing as how HERCs are apparently destroyed the moment they fall over, these tanks were extremely useful in their single appearance.
- Action Man (2000): The Quake suit of Powered Armor was designed by Japanese scientists to study tremors, but it could also produce them. It is subsequently stolen by a fat janitor who uses it to become the supervillain "Quake".
- Armodrillo from Ben 10: Ultimate Alien is a robotic-like creature known as a Talpaedan who can use his drill arms to create small earthquakes or quickly create tunnels which can also generate vibrations.
- In the pilot episode of Goof Troop, Pete plants one of those old jiggling exercise machines to the foundation of the house next door and creates mini-quakes to scare away potential buyers so he can use the land to create his own backyard paradise.
- Dr. Wily used one in the Mega Man cartoon.
- Seismo from Mixels is a living one, with giant feet that shake the earth when he stomps them. Unfortunately for those around him, he gets ultra-nervous very easy and has the tendency to tap his feet when he does...
- Lilo & Stitch: The Series: Experiment 513 (named Richter) is a living example. He is designed to create earthquakes by slamming his tail at the ground.
- In the Pac-Man short "The Great Pac-Quake", Mezmaron sends the Ghost Monsters out with a machine to distract the people of Pacland with an earthquake so the ghosts can steal the secret map from the local museum.
- In the Porky Pig cartoon "Porky the Rainmaker", Porky has some weather pills that make whatever weather phenomenon is written on it. One chicken eats an earthquake pill, causing it to have personal earthquakes. When it holds onto something for a brace, that ends up shaking, too.
- In an episode of Road Runner, Wile E. Coyote makes the Road Runner eat the earthquake pills. But, of course, he forgot to Read the Fine Print on the pill bottle.
- Rumble in Transformers: Generation 1 is able to use his fist as piledrivers and create small earthquakes with them.
- The 1942 Superman Theatrical Cartoons Superman cartoon Electric Earthquake has one — created by a Native-American Mad Scientist who wants to reclaim Manhattan for his people, believing it was taken by fraud.
- Teenage Mutant Ninja Turtles (1987): The Technodrome has one built-in.
- Nikola Tesla claimed to have built one, but when it was tested on MythBusters it failed to create an earthquake, although it was able to sustain some significant vibrations.
- Hydrogen Bombs do this, particularly when someone buries them. Though one air-detonated bomb, the Tsar Bomba, explosion was so big that it could be felt anywhere and everywhere. Strangely, though, despite the wide swath of earth that is shook by an underground blast, there is little damage that is earthquake-related.