Pahoehoe moves along fairly rapidly with viscous lobes oozing over one another. Shown below is the toe of a pahoehoe flow. This is what the inside of a pahoehoe lobe looks like. The holes, or vesicles, were created by gases trapped in the solidifying lava. A large bomb can be seen in the middle of the photograph.
Volcanic activity is accompanied by faulting and earthquakes.
Very often, an early sign of an impending eruption is swelling of the ground over the rising magma, causing splitting of the volcano's surface. Noxious hot gases emerge from vents all over Kilauea. Elemental sulfur and other minerals precipitate around the steam vents. This second set of photos comes from Mount Kelimutu on Flores Island in Indonesia. Indonesia is located along a complex convergent plate boundary.