I just created a world and was amazed to find a volcano under the ice of a frozen ocean =O. The only downside is that the volcano is in the very bottom left of the region tile and the closest land is far away. But anyways here is the worldgen info as well as some screen shots.
I have not played it through till high summer, but it says that it is in a temperate region so perhaps the ocean will melt and cause extreme lag/awesome.
The actual embark site is a 3 level thick ice sheet with a volcano at the bottom lefthand corner of the map. There is a huge hole over the top and the sides are just ice until the rim of the volcano.
I think it is time for a sub oceanic base?
(tileset is mayday)
Location
Worldgen info (For v 0.31.08)
[WORLD_GEN]
[TITLE:VOLCANOS AND OCEANS]
[SEED:830566192]
[HISTORY_SEED:437012752]
[NAME_SEED:3758296224]
[CREATURE_SEED:4253423296]
[DIM:129:129]
[EMBARK_POINTS:10000]
[END_YEAR:1050]
[BEAST_END_YEAR:200:80]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:0]
[ELEVATION:1:400:1600:1600]
[RAINFALL:0:100:200:200]
[TEMPERATURE:25:75:200:200]
[DRAINAGE:0:100:200:200]
[VOLCANISM:0:100:200:200]
[SAVAGERY:0:100:200:200]
[ELEVATION_FREQUENCY:4:2:0:1:0:1]
[RAIN_FREQUENCY:1:1:1:1:1:1]
[DRAINAGE_FREQUENCY:1:1:1:1:1:1]
[TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
[SAVAGERY_FREQUENCY:1:1:1:1:1:1]
[VOLCANISM_FREQUENCY:1:1:1:1:1:1]
[TITAN_NUMBER:9]
[TITAN_ATTACK_TRIGGER:80:100000:100000]
[DEMON_NUMBER:28]
[GOOD_SQ_COUNTS:6:63:0]
[EVIL_SQ_COUNTS:6:63:0]
[PEAK_NUMBER_MIN:10]
[PARTIAL_OCEAN_EDGE_MIN:0]
[COMPLETE_OCEAN_EDGE_MIN:4]
[VOLCANO_MIN:100]
[REGION_COUNTS:SWAMP:66:0:0]
[REGION_COUNTS:DESERT:66:0:0]
[REGION_COUNTS:FOREST:264:0:0]
[REGION_COUNTS:MOUNTAINS:528:0:0]
[REGION_COUNTS:OCEAN:528:0:0]
[REGION_COUNTS:GLACIER:16:0:0]
[REGION_COUNTS:TUNDRA:33:0:0]
[REGION_COUNTS:GRASSLAND:528:0:0]
[REGION_COUNTS:HILLS:528:0:0]
[EROSION_CYCLE_COUNT:250]
[RIVER_MINS:40:40]
[PERIODICALLY_ERODE_EXTREMES:1]
[OROGRAPHIC_PRECIPITATION:1]
[SUBREGION_MAX:2750]
[CAVERN_LAYER_COUNT:1]
[CAVERN_LAYER_OPENNESS_MIN:0]
[CAVERN_LAYER_OPENNESS_MAX:100]
[CAVERN_LAYER_PASSAGE_DENSITY_MIN:0]
[CAVERN_LAYER_PASSAGE_DENSITY_MAX:20]
[CAVERN_LAYER_WATER_MIN:0]
[CAVERN_LAYER_WATER_MAX:20]
[HAVE_BOTTOM_LAYER_1:1]
[HAVE_BOTTOM_LAYER_2:1]
[LEVELS_ABOVE_GROUND:15]
[LEVELS_ABOVE_LAYER_1:25]
[LEVELS_ABOVE_LAYER_2:1]
[LEVELS_ABOVE_LAYER_3:1]
[LEVELS_ABOVE_LAYER_4:5]
[LEVELS_ABOVE_LAYER_5:2]
[LEVELS_AT_BOTTOM:1]
[CAVE_MIN_SIZE:5]
[CAVE_MIN_SIZE:5]
[CAVE_MAX_SIZE:25]
[MOUNTAIN_CAVE_MIN:5]
[NON_MOUNTAIN_CAVE_MIN:10]
[ALL_CAVES_VISIBLE:1]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:10]
[TOTAL_CIV_POPULATION:15000]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:8000:1056:528]
[RAIN_RANGES:528:1056:528]
[DRAINAGE_RANGES:528:1056:528]
[SAVAGERY_RANGES:528:1056:528]
[VOLCANISM_RANGES:528:1056:528]