Complex sentence: Even large submarine eruptions may not disturb the ocean surface due to the rapid cooling effect of water as compared to air, and increased buoyancy, which often forms steep pillars over volcanic vents as compared to above-surface volcanoes.
Split into simpler sentences: Even large submarine eruptions may not disturb the ocean surface. Because of the rapid cooling effect of water as compared to air, and increased buoyancy, submarine volcanoes often form rather steep pillars over their volcanic vents as compared to above-surface volcanoes.