The 2001 Taupō Fault Belt Seismicity as Evidence of Magma‐Tectonic Interaction at Taupō Volcano

The Taupō Volcanic Zone (TVZ) is the southern extent of the Tonga‐Kermadec volcanic arc and encompasses the Taupō Rift, with the two structures accommodating extension through the central North Island of New Zealand via magmatic and tectonic processes, respectively. Interplay between components of the TVZ and Taupō Rift are evident at Taupō volcano, which exhibits periods of increased seismicity on a decadal scale. One period of increased seismicity occurred in 2001 outside the caldera in the adjacent Taupō Fault Belt. We use seismological analysis to detect and characterize the Taupō Fault Belt seismicity, which aligns in clusters close to active faults, and was preceded by a large cluster of earthquakes beneath Lake Taupō's Western Bay. This cluster and a temporal change in the local stress field imply that a magmatic intrusion beneath the Western Bay initiated the unrest in the fault belt. Our analysis suggests this intrusion may have occurred outside the silicic reservoir at Taupō and that it represents an example of interaction between the regional tectonic and deep mafic magmatic systems at Taupō. Plain Language Summary The Taupō Volcanic Zone (TVZ) is a large area of volcanism that spans the central North Island of New Zealand. Active volcanism coincides with continental extension, named the Taupō Rift and both are the result of the interaction between the Australian and Pacific plates occurring offshore. At the center of the TVZ is Taupō volcano, a large caldera which undergoes regular phases of seismic unrest involving large numbers of earthquakes and ground shaking. A period of unrest in 2001 contrasts with the other unrest episodes in that most of the seismicity was concentrated in the Taupō Fault Belt rather than within the adjacent caldera, and we hypothesize that its occurrence may provide insight into the interaction between magmatic and tectonic processes around Taupō volcano. Our analysis suggests that the earthquakes in 2001 first occurred beneath Taupō volcano, initiating subsequent seismic activity in the Taupō Fault Belt and temporarily altering the surrounding stress state. We infer that the initial group of earthquakes beneath Taupō volcano coincided with and were triggered by a magmatic intrusion. Therefore, the seismicity in 2001 highlights an example of interaction between the tectonic and deep magmatic systems at Taupō volcano. Key Points Matched‐filter detection identified 3,782 earthquakes of ML 0.0–2.6 beneat