Salton Trough

[2] The Salton Trough is classified as a distinct section of the Basin and Range Province within the Intermontane Plateaus division.

The northwestern end of the trough starts at the San Gorgonio Pass in Riverside County and extends 115 miles (185 km) southeast to the Gulf of California.

[6] The Niland Geyser is one of dozens of mudpots and mud volcanoes in the Salton Trough but is the only one in the world known to have moved significantly, affecting the Union Pacific Railroad, California State Route 111, and other infrastructure since 2018.

[7][8] The Salton Trough is a result of crustal stretching and sinking caused by the combined actions of the San Andreas Fault and the East Pacific Rise, particularly the Gulf of California Rift Zone (GCRZ), the northernmost portion of the East Pacific Rise.

The GCRZ and the San Andreas Fault both terminate near the south end of the Salton Sea, in an area called the Brawley Seismic Zone.