Four Craters Lava Field Four Craters Lava Field Four Craters Lava Field is a basaltic volcanic field located south east of Newberry Caldera in the U.S. state of Oregon. The volcanic field covers about 30 square kilometers. Four Pleistocene cinder cones are the source of the flows in the field and are aligned along a fissure trending N 30° W. The cones rise 75 to 120 meters above the flows and the distance between the northern most and southern most cones is about 3.5 kilometers. Closely related to the Four Craters lava field is Crack-in-the-Ground located at the southwest corner of the field. The
Lava buried by the advancing flow. This produces a layer of lava fragments both at the bottom and top of an aā flow. Accretionary lava balls as large as are common on aā flows. Aā is usually of higher viscosity than pāhoehoe. Pāhoehoe can turn into aā if it becomes turbulent from meeting impediments or steep slopes. The sharp, angled texture makes aā a strong radar reflector, and can easily be seen from an orbiting satellite (bright on Magellan pictures). Aā lavas typically erupt at temperatures of . The word is also spelled "aa", "aa", "aa", and "a-aa", and pronounced .