SOURCE FUNCTION DETERMINATION OF GLASS-CAPILLARY BREAKS

Abstract

Glass capillaries of various sizes were broken on a steel plate and the source force was determined from the epicentral displacement. The rise time and magnitude of the source force were directly determined from the time domain signals without a deconvolution procedure, under the assumption of the source force as a ramp force. The rise time of signals at the arrival time of longitudinal waves corresponded to the rise time of the source force, and the signal level at the arrival time of transverse waves was proportional to the magnitude of the ramp force. The magnitude of the source function showed a different linearity depending on the ID/OD, the larger the force the larger the cross-sectional area. The rise time of glass capillary breaks is shown to be equivalent to the time required for capillary fracture, the longer the rise time the thicker the capillary in mean diameter. The average crack velocity in the glass capillary determined from the relationship between the rise time and the capillary diameters was 0.284c(l), where c(l) is the longitudinal wave velocity.