Landslide ak. Lee Broder believed himself to be a hard-hitting, beer drinking Southern redneck. He possessed a natural resistance to any physical harm and superhuman strength. His whole body was built unnaturally massive and his extremities were larger than those of normal humans.
Lee remembered how "Xavier" approached him after another bar brawl. Lee had just beaten up everyone else in the bar including the owner, who was afraid that Lee's actions would run him out of business. "Xavier" told Lee that he must learn to control his temper and powers. Lee told "Xavier" that only people that wanted to be beat up called him Lee, but "Xavier" ignored the threat and asked Lee to join the X-Men.
Landslide can cause intense vibrations and tremors in anything, animate or inanimate, that he touches. He can cause earthquake level tremors, or cause injury to a living thing on contact. He is limited by his need to directly touch an object, and he cannot project his power across a distance.
Landslide is also a pacifist, and, while willing to use force when necessary, he will often try to solve problems through discussion or less violent means.
It was Landslide who was sent to the surface to investigate the tremors caused by Avalanche, and he acted independently of the group in that adventure.