When molten rock is inside the earth, it’s called magma, but as soon as it erupts from a volcanic vent, it becomes lava. Lavas like basalt can flow like a red-hot river, while dacite and rhyolite lavas can ooze slowly out of the volcano to form a lava dome. Some lavas can flow faster than a person can run, but normally lava travels slowly enough for people to move out of its way. Everything in the path of an advancing flow can be knocked over, surrounded, burned or buried. Scientists are able to