No latest activity reported for North Sister Field.

Below is a summary of eruption dates and Volcanic Explosivity Indices (VEI).

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Green J, Short N M, 1971. {Volcanic Landforms and Surface Features: a Photographic Atlas and Glossary}. New York: Springer-Verlag, 519 p

Hildreth W E, 2007. Quaternary magmatism in the Cascades--geologic perpectives. {U S Geol Surv Prof Pap}, 1744: 1-125

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. {IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior}.

Sarna-Wojcicki A M, Champion D E, Davis J O, 1983. Holocene volcanism in the conterminous United States and the role of silicic volcanic ash layers in correlation of latest Pleistocene and Holocene deposits. {In}: Wright H E (ed) {Late-Quaternary Environments of the United States}, Minneapolis: Univ Minnesota Press, 2: 52-77

Schmidt M E, Grunder A L, 2009. The evolution of North Sister: a volcano shaped by extension and ice in the central Oregon Cascade Arc. {Geol Soc Amer Bull}, 121: 643-662

Scott W E, Gardner C A, Sarna-Wojcicki A M, 1989. Guidebook for field trip to the Mount Bachelor-South Sister-Bend area, central Oregon High Cascades. {U S Geol Surv Open-File Rpt}, 89-645: 1-68

Taylor E M, 1968. Roadside geology, Santiam and McKenzie Pass Highways, Oregon. {Oregon Dept Geol Min Ind Bull}, 62: 3-34

Taylor E M, 1981. Roadlog for central High Cascade geology, Bend, Sisters, McKenzie Pass, and Santiam Pass, Oregon. {U S Geol Surv Circ}, 838: 59-83

Williams H, 1944. Volcanoes of the Three Sisters region, Oregon Cascades. {Univ Calif Pub Geol Sci}, 27: 37-84

North and Middle Sister volcanoes anchor the northern end of the Three Sisters volcano group that dominates the landscape of the central Oregon Cascades. Glaciers have deeply eroded the Pleistocene andesitic-dacitic North Sister stratovolcano, exposing the volcano's central plug. North Sister was constructed over the remnants of the basaltic Little Brother shield volcano to the NW. Construction of the main edifice ceased at about 55,000 yrs ago, but N-S-trending fissures north of the volcano were active until at least the latest Pleistocene. Middle Sister volcano, also over 3000 m in elevation, is located only 2 km to the south. The basaltic-to-rhyolitic Middle Sister and its flank vents is less-eroded, but Holocene activity in the North Sister area is restricted to a group of cinder cones north and NW of the North Sister that have produced a series of fresh-looking blocky lava flows on both sides of McKenzie Pass. The youngest lava flow, from Collier Cone, which was erupted about 1600 years ago and traveled 13.5 km to the west, is a prominent feature of the McKenzie Pass area.