From LSWiki

Earth Resistance is DEAD! R.I.P. It isn't here anymore. Don't bother looking for it in-game.

Class: Resistance Skills
Attribute: Vitality
Pedagogy: Body Alteration
Practitioner Term: Earth Resistor
Hidden Skill

This skill represents the conditioning of one's body to resist being damaged by elemental earth and essences that partake of its
nature.

Earth resistance can be increased by exposure to earth damage, changing more quickly according to one's somatic adaptability.  It
will decay over time, weakening more quickly according to one's somatic adaptability.

See Also: earth affinity

Trainers