SAPS - An automated and networked seismological acquisition and processing system

A PC-based digital data acquisition and processing system was developed and implemented on two PCs linked by a peer-to-peer LAN. Sixteen channels are sampled with a rate of 200 Hz. The acquisition is performed continuously in sequenced files on one PC using the IASPEI-released XRTP software. The length of the elementary files is adjustable; we used 90 sec in this application. The second PC runs a program to organize automatically the following processing steps: (i) moving the raw data from the first to the second PC; (ii) filtering the data for running a 'Rex Allen'-like picker for P waves on each elementary file; (iii) concatenating three consecutive elementary files if the detection criteria are fulfilled; (v) decoding a fast time code (Lennartz-style); (v) discriminating between local and teleseismic events; (vi) plane-wave method location and m(b) determination for teleseisms; (vii) picking S waves, determining coda duration and locating local events; (viii) conversion of PC-SUDS into GSE format and 'feeding' a Data Request Manager with phases, locations and waveforms; (ix) sending phases and location, via e-mail, minutes after detection, and a 'health status' every hour, to the system manager; (x) plotting the raw data, the picks and printing the location results; and (xi) archiving data and results locally and on a remote workstation. The system has been running since April 1994 with data from the telemetered network of the Upper Rhinegraben. Being modular, the system can be extended and upgraded easily. Loss Df data is avoided by using large hard disks as temporary data buffers and file mirroring on different hard disk drives.