Io is Jupiter's innermost and second-smallest Galilean moon. Discovered by Galileo in 1610, named after mythological Io. Has highest density and strongest surface gravity among moons. Composed primarily of silicate rock with molten iron core
Laccolith is a dome-shaped intrusive rock with level base fed by underground conduit. Forms when magma spreads horizontally through crust, forcing overlying strata upward. Critical radius determines when sill becomes laccolith. Laccoliths typically form at shallow crust depths from intermediate composition magma
Archipelago of volcanic islands located 900 km west of South America. Straddles equator, covering 7,880 km² land and 45,000 km² ocean. Largest island is Isabela, measuring 2,250 km². Volcanism has been ongoing for at least 20 million years
Volcanism occurs when solids, liquids, gases erupt from solid-surface bodies. Heat from internal processes, like radioactive decay or tidal heating, triggers volcanism. Mantle temperature must reach half its melting point for volcanism to occur
Andes spans 5,500 miles from South America's southern tip to Caribbean coast. System consists of parallel mountain ranges called cordilleras. Highest peak is Mount Aconcagua at 22,831 feet. Divided into Southern, Central, and Northern Andes
Extends 5,500 miles from South America's southern tip to Caribbean coast. Contains highest peaks in Western Hemisphere, including Mount Aconcagua (22,831 feet). Consists of parallel mountain ranges (cordilleras) and intervening plateaus. Divided into Southern, Central, and Northern Andes regions