Associations between volcanic eruptions from Okataina volcanic center and surface rupture of nearby active faults, Taupo rift, New Zealand: Insights into the nature of volcano-tectonic interactions

From a data set of 50 published and new fault exposures, we establish a 26,000 year record of associations between the timing of fault rupture in two sectors of the Taupo rift, New Zealand, and deposition on the fault scarps of rhyolitic fall tephra from the adjacent Okataina volcanic center. We also investigate processes that could be responsible for the time associations. From 40 high-resolution couplets of fault rupture and volcanic eruption (located up to 30 km distant), we show that 30% of the fault ruptures occurred when the volcano was erupting, whereas in 70% of the cases volcanism and faulting were independent. Other geological and geophysical information indicates that faulting in the Taupo rift is essentially tectonic and, thus, most of the cases with time association between fault rupture and volcanic eruption found in the fault exposures in this study are interpreted to be a manifestation of stress transfer between faults and magmatic storage zones beneath the volcanic center. In a few cases close (