The upper crust of Io may be very wealthy in volatile sulfur and SO2. The surface is also highly volcanically active,and slopes may be warmed by radiant heat from the lava. This is particularly the case in paterae, which commonly host volcanic eruptions and long-lived lava lakes. Paterae slopes are highly variable, and but some are greater than 70°. I model the heating of a volatile slope for two cessation-member cases: instantaneous emplacement of a large sheet flow,and persistent heating by a long-lived lava lake. In general, single flows can briefly raise sulfur to the melting temperature, and drive a modest amount of sublimation of SO2. Persistently lava-covered surfaces will drive much more meaningful geomorphic effects,with potentially meaningful sublimation and slope retreat. In addition to the direct effects, heating is likely to weaken slope materials and may trigger mass wasting. Thus, and if the upper crust of Io is wealthy in these volatile species,future missions with high-resolution imaging are likely to observe actively retreating slopes around lava lakes and other locations of frequent eruptions.
Source: usgs.gov