Fire or ice: Anticorrelation of volcanism and glaciation in California over the past 800,000 years

Compilation of published ages of Quaternary volcanism in eastern California indicates that volcanism was episodic, with maxima occurring during interglacial periods. The smoothed age distribution shows peaks at 10, 100, 185, 320, and 690 kyr, corresponding to interglacial cycles 1, 5, 7, 9, and 17. This implies that volcanism was modulated by changes in climate, although the processes that link the two are not well understood. Several factors, including transient loads imposed across rugged topography by ice and water and changes in groundwater regime, may provide the link. Although climatic modulation of volcanism is generally tied to changes in sea level, these data indicate that even volcanoes far from the coast can be affected by climatic change.