578 VOLCANOES Figure 18 False colour radar image of seven eruptive domes, each 25 km in diameter, overlying one another, on Venus: pos sibly domes of viscous silicic lava? (NASA image) a major earthquake in Chile in 1960 is recorded as activating several Andean volcanoes and a major earthquake in Sicily is recorded as having been preceded three days earlier by an eruption of Etna Extra-terrestrial volcanoes Active volcanoes are known on Jupiter’s satellite Io (Figure 15), and huge extinct volcanoes occur on Mars and Venus (Figures 16, 17 and 18) Venus’s thick CO2 rich atmosphere is believed to be volcanically sourced See Also Earth: Mantle; Crust Engineering Geology: Natural and Anthropogenic Geohazards Lava Mantle Plumes and Hot Spots Solar System: Venus; Mars; Jupiter, Saturn and Their Moons Figure 17 (A) False colour radar image of a volcanic crater on Venus (35 km diameter at summit) Note lava flow which has pass ed through a breach in the wall at top; also the eroded (?) lateral slope ridges and gullies which suggest Earth like processes operating (NASA image) (B) The Gora Konder crater, diameter 22 km, Siberia: in remote terrain, the origin, volcanic or impact is unknown, illustrating the difficulty of differentiating impact and volcanism on physiography alone: the similarity of the flank ridges and gullies to a) is striking (NASA, Shuttle Discovery image) Further Reading Davies A and Bowler S (2001) Extra terrestrial active vol canism Geoscientist 11(8): Green J and Short NM (1971) Volcanic Landforms and Surface Features A Photographic Atlas and Glossary New York, Heidelberg, Berlin: Springer