SAPS - AN AUTOMATED AND NETWORKED SEISMOLOGICAL ACQUISITION AND PROCESSING SYSTEM

A PC-based digital data acquisition and processing system was develope d and implemented on two PCs linked by a peer-to-peer LAN. Sixteen cha nnels are sampled with a rate of 200 Hz. The acquisition is performed continuously in sequenced files on one PC using the IASPEI-released XR TP 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) co ncatenating three consecutive elementary files if the detection criter ia are fulfilled; (v) decoding a fast time code (Lennartz-style); (v) discriminating between local and teleseismic events; (vi) plane-wave m ethod location and m(b) determination for teleseisms; (vii) picking S waves, determining coda duration and locating local events; (viii) con version of PC-SUDS into GSE format and 'feeding' a Data Request Manage r with phases, locations and waveforms; (ix) sending phases and locati on, via e-mail, minutes after detection, and a 'health status' every h our, to the system manager; (x) plotting the raw data, the picks and p rinting the location results; and (xi) archiving data and results loca lly and on a remote workstation. The system has been running since Apr il 1994 with data from the telemetered network of the Upper Rhinegrabe n. Being modular, the system can be extended and upgraded easily. Loss Df data is avoided by using large hard disks as temporary data buffer s and file mirroring on different hard disk drives.