Global Volcanism Program | Image GVP-10163
The rugged eastern crater rim of Santa Ana volcano rises more than 100 m above the crater floor. The eastern wall is composed of breccias, scoria layers, thin lava flows, and dikes. Thick sequences of lava flows are exposed in the northern and southern crater walls and are overlain by bedded phreatomagmatic tephra layers up to 100 m thick on the southern side.
Photo by Lee Siebert, 2002 (Smithsonian Institution).