Seismic sense

"earth"

- I see with earthbending. It’s kind of like seeing with my feet. I can feel the vibrations in the earth, and I can see where everything is. You, that tree, even those ants.



Seismic Sense is a sub-skill of Earthbending. Basically, it constitutes a physical sense. Earthbenders can use it to detect vibrations in the ground and perceive objects and their enviroment through it. The sense was first demonstrated by Toph in The Blind Bandit during her fight with The Boulder

Uses
First and foremost of Seismic Sense's applications is the ability to perceive their surroundings. By sensing vibrations in the ground, earthbenders can perceive their surroundings as precisely as normal sight. Practioners can use the sense to detect things out of their line of sight, even right behind them. Obstacles that would normally obstruct regular vision, such as walls and thick dust clouds, are ineffective against Seismic Sense.



Notably, Seismic Sense also allows earthbenders to bend metal. Earthbenders who do not possess Seismic Sense cannot do so, but not for lack of potential. Minute amounts of earth still exist in metal, but are so small and elusive that normal earthbenders cannot "grab" them. Seismic Sense users, however, can detect the small amounts of earth still present in the metal, enabling them to bend it.

Another ability enabled by Seismic Sense is lie detection. The sense allows Earthbenders to sense the interiors of humans, and any changes in their status. Since humans have a physical reaction when they lie, earthbenders who use Seismic Sense can tell when one happens. However, the reaction can be suppressed when lying, making earthbenders unable to tell if the statement is a lie. By extension, Seismic Sense should also allow users to sense internal injuries.

Limitations
Seismic Sense is not without its limitations. Seismic sense only detects things in contact with the ground; objects floating in water or thrown in the air are undetectable. The practioner must also be in contact with solid ground to use the sense at all; again, if the user is in the air or water, or even standing on a non-earth solid such as ice, he will be unable to sense anything. Sand, although an earth-based substance, is not firm like normal earth, and renders Seismic Sense "fuzzy" and very imprecise. Uninterrupted contact with the ground is preferred for the user- an object such as a shoe sole interferes with the sense. The sense also has considerably less range than uninterrupted sight.

History
The earthbending badgermoles were the first users of Seismic Sense. Naturally blind, the badger moles use their ability to navigate their world. It especially helps them navigate the ever-changing tunnel network of the Cave of Two Lovers.

The first known human practioner of the sense was Toph Bei-Fong. Because she was born blind, she developed the sense from birth just like the badger moles. It is unlikely, though, that all earthbenders born blind develop the sense, since Toph's parents did not expect the ability. Toph used the ability to develop a form of earthbending separate from normal technique. Along with this, she used Seismic Sense to discover the abilities of lie detection and metalbending.

The only other human practioner of Seismic Sense is Aang. Taught by Toph, Aang is fully capably of using the sense to perceive things and movement out of his line of vision or while blindfolded. He has not yet demonstrated the abilities to detect lies or metalbend, though.

It is possible that Bumi knows about Seismic Sense, since he told Aang to find an Earthbending teacher who "waits and listens before striking", which is what a Seismic Sense practioner does.