Boring Lava Field subsurface regions near Aurora and Curtis, and these intrusions have been associated with normal faulting at Parrett and Petes Mountain, Aurora, Curtis, and Swan Island (along the Molalla River). Faults together with igneous intrusions are usually accompanied by stretching and doming as a result of magma influxes or collapses from the evacuation of the magma flows. Similarly, faults north of Oregon City might have resulted from subsidence after magma chambers emptied or lava was extruded as a result of Boring Lava eruptions. Some of the Boring lava vents are known to truncate hydrogeologic units in the surrounding area. Eruptive vents
Magma chamber Magma chamber A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is under great pressure, and, given enough time, that pressure can gradually fracture the rock around it, creating a way for the magma to move upward. If it finds its way to the surface, then the result will be a volcanic eruption; consequently, many volcanoes are situated over magma chambers. These chambers are hard to detect deep within the Earth, and therefore most of those known are close to the surface, commonly between