Minor-planet moon Herculina does not have a significant satellite. There were other similar reports of asteroids having companions (usually referred to as satellites) in the following years. Also, a letter in "Sky & Telescope" magazine at this time pointed to apparently simultaneous impact craters on Earth (for example, the Clearwater Lakes in Quebec), suggesting that these craters were caused by pairs of gravitationally-bound objects. In 1993, the first asteroid moon was confirmed when the Galileo probe discovered the small Dactyl orbiting 243 Ida in the asteroid belt. The second was discovered around 45 Eugenia in 1998. In 2001, 617 Patroclus and its
Craters of the Moon National Monument and Preserve has been implicated. This hot spot was under the Craters of the Moon area some 10 to 11 million years ago but 'moved' as the North American Plate migrated southwestward. Pressure from the hot spot heaves the land surface up, creating fault-block mountains. After the hot spot passes the pressure is released and the land subsides. Leftover heat from this hot spot was later liberated by Basin and Range-associated rifting and created the many overlapping lava flows that make up the Lava Beds of Idaho. The largest rift zone is the Great Rift; it is from this 'Great Rift fissure