I was just now messing around with generating worlds and playing with the volcanism levels and variance, and generated a world with 25/100 min/max and a very high variance (1600) and just about every place I embark, even if perfectly flat and nowhere near a volcano, has SMR mountains with blue spires and lava flows hundreds of levels in the sky, if the game doesn't simply crash when I hit 'e' to embark...
Worldgen:
[WORLD_GEN]
[TITLE:FUBAR]
[DIM:65:65]
[EMBARK_POINTS:1274]
[END_YEAR:149]
[BEAST_END_YEAR:100:80]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:0]
[ELEVATION:100:400:1600:1600]
[RAINFALL:0:100:1600:1600]
[TEMPERATURE:25:75:101:101]
[DRAINAGE:0:0:101:101]
[VOLCANISM:25:100:1600:1600]
[SAVAGERY:0:100:101:101]
[ELEVATION_FREQUENCY:1:1:1:1:1:1]
[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]
[MEGABEAST_CAP:4]
[SEMIMEGABEAST_CAP:9]
[TITAN_NUMBER:3]
[TITAN_ATTACK_TRIGGER:80:0:100000]
[DEMON_NUMBER:22]
[GOOD_SQ_COUNTS:0:0:0]
[EVIL_SQ_COUNTS:0:0:0]
[PEAK_NUMBER_MIN:0]
[PARTIAL_OCEAN_EDGE_MIN:0]
[COMPLETE_OCEAN_EDGE_MIN:0]
[VOLCANO_MIN:18]
[REGION_COUNTS:SWAMP:0:0:0]
[REGION_COUNTS:DESERT:0:0:0]
[REGION_COUNTS:FOREST:0:0:0]
[REGION_COUNTS:MOUNTAINS:0:0:0]
[REGION_COUNTS:OCEAN:0:0:0]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:0:0:0]
[REGION_COUNTS:HILLS:0:0:0]
[EROSION_CYCLE_COUNT:1000]
[RIVER_MINS:4:4]
[PERIODICALLY_ERODE_EXTREMES:1]
[OROGRAPHIC_PRECIPITATION:1]
[SUBREGION_MAX:2750]
[CAVERN_LAYER_COUNT:1]
[CAVERN_LAYER_OPENNESS_MIN:100]
[CAVERN_LAYER_OPENNESS_MAX:100]
[CAVERN_LAYER_PASSAGE_DENSITY_MIN:0]
[CAVERN_LAYER_PASSAGE_DENSITY_MAX:0]
[CAVERN_LAYER_WATER_MIN:20]
[CAVERN_LAYER_WATER_MAX:30]
[HAVE_BOTTOM_LAYER_1:1]
[HAVE_BOTTOM_LAYER_2:1]
[LEVELS_ABOVE_GROUND:15]
[LEVELS_ABOVE_LAYER_1:20]
[LEVELS_ABOVE_LAYER_2:1]
[LEVELS_ABOVE_LAYER_3:1]
[LEVELS_ABOVE_LAYER_4:1]
[LEVELS_ABOVE_LAYER_5:100]
[LEVELS_AT_BOTTOM:1]
[CAVE_MIN_SIZE:5]
[CAVE_MAX_SIZE:25]
[MOUNTAIN_CAVE_MIN:6]
[NON_MOUNTAIN_CAVE_MIN:12]
[ALL_CAVES_VISIBLE:0]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:10]
[TOTAL_CIV_POPULATION:15000]
[SITE_CAP:264]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:0:0:0]
[RAIN_RANGES:0:0:0]
[DRAINAGE_RANGES:0:0:0]
[SAVAGERY_RANGES:0:0:0]
[VOLCANISM_RANGES:0:0:0]
edit- Well I just generated a few more worlds with those settings and they seem to be normal, so I dunno wtf is going on with these odditys.