The 2001 Taupo Fault Belt Seismicity as Evidence of Magma-Tectonic Interaction at Taupo Volcano

The Taupo Volcanic Zone (TVZ) is the southern extent of the Tonga-Kermadec volcanic arc and encompasses the Taupo 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 Taupo Rift are evident at Taupo 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 Taupo Fault Belt. We use seismological analysis to detect and characterize the Taupo Fault Belt seismicity, which aligns in clusters close to active faults, and was preceded by a large cluster of earthquakes beneath Lake Taupo'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 Taupo and that it represents an example of interaction between the regional tectonic and deep mafic magmatic systems at Taupo.

Automated summary

The Taupo Volcanic Zone is part of the Tonga-Kermadec volcanic arc in New Zealand and is characterized by extensional tectonic processes and magmatic activities. The seismicity in the Taupo Fault Belt, which is adjacent to the Taupo volcano, is influenced by regional tectonic and deep mafic magmatic systems. An increase in seismic activity in 2001 outside the caldera suggests that a magmatic intrusion beneath Lake Taupo's Western Bay initiated the unrest in the fault belt.