B-type volcanic earthquakes at White Island volcano, New Zealand

摘要: Abstract B-type volcanic earthquakes at White Island have almost all their energy in the band 0.5–4 Hz, around a dominant spectral peak of about 2 Hz. A high degree similarity waveforms suggests that originate from volume 100 m 3 , and process generates them is repetitive. At distance 1 km active crater particle motion events an initial P-wave, followed 0.5 seconds later by horizontally polarised S-wave then wave unknown type. The exact mechanism for unknown, however, absence higher harmonics implies they cannot be caused resonance gas or magma within pipe-like structure, P- S-waves suggest simple shear-induced rock fracture hot ductile medium.