Complex sentence: Lapilli tuffs are a very common form of volcanic rock typical of rhyolite, andesite and dacite pyroclastic eruptions, where thick layers of lapilli can be deposited during a basal surge eruption.
Split into simpler sentences: Lapilli tuffs are a very common form of volcanic rock typical of rhyolite, andesite and dacite pyroclastic eruptions. Here, thick layers of lapilli can be deposited during a basal surge eruption.