| Long period seismic events observed under many volcanoes are often interpreted in relation
to any fluid-filled resonator. The kinematic mechanisms have been also studied
seismologically in terms of seismic moment, and some of them indicate the geometry of a
‘tensile’ crack. In Volcanology, Chouet (1986) first solved the elasto-dynamic equations
coupling with the fluid using a finite difference method, similarly to ‘shear’ crack
problems treated in seismology, and this model is always a reference (Chouet and
Motoza, 2013). But only a few studies have treated such dynamic problems (e.g.
Yamamoto and Kawakatsu, 2009), while dynamic ‘shear’ cracks have been studied
progressively in these two decades in seismology. This study presents a boundary integral
equation method (BIEM) in the time domain to solve a ‘tensile’ crack resonance. The
time-domain BIEM is often used for a ‘shear’ crack thanks to its accuracy, efficiency and
flexibility, and usually adopted with an explicit approach (a time step Δt is short enough
to an element size Δs so that any grid influences instantaneously itself, Δt |