Vesicular texture Vesicular texture Vesicular texture is a volcanic rock texture characterized by a rock being pitted with many cavities (known as vesicles) at its surface and inside. This texture is common in aphanitic, or glassy, igneous rocks that have come to the surface of the earth, a process known as extrusion. As magma rises to the surface the pressure on it decreases. When this happens gasses dissolved in the magma are able to come out of solution, forming gas bubbles (the cavities) inside it. When the magma finally reaches the surface as lava and cools, the rock solidifies around the gas
Lava dome extrusive products of lava domes. Domes may reach heights of several hundred meters, and can grow slowly and steadily for months (e.g. Unzen volcano), years (e.g. Soufrière Hills volcano), or even centuries (e.g. Mount Merapi volcano). The sides of these structures are composed of unstable rock debris. Due to the intermittent buildup of gas pressure, erupting domes can often experience episodes of explosive eruption over time. If part of a lava dome collapses and exposes pressurized magma, pyroclastic flows can be produced. Other hazards associated with lava domes are the destruction of property from lava flows, forest fires, and lahars