"It's a horizontal motion of two pieces of the Earth's crust on either side of a vertical crack in the Earth,"
VOA: standard.2010.01.13
According to tectonic theory, the surface of the Earth is made up of a patchwork of massive rigid plates, about 80km (50 miles) thick, which float in slow motion on top of the Earth's hot, pliable interior.
Compared with the sluggish air on Earth, the Martian atmosphere is in constant motion: between the surface and six feet above it, temperatures can vary by as much as sixty degrees.