PARALLEL 3-D PSEUDOSPECTRAL SIMULATION OF SEISMIC-WAVE PROPAGATION

Three-dimensional pseudospectral modeling for a realistic scale proble m is still computationally very intensive, even when using current pow erful computers. To overcome this, we have developed a parallel pseudo spectral code for calculating the 3-D wavefield by concurrent use of a number of processors. The parallel algorithm is based on a partition of the computational domain, where the field quantities are distribute d over a number of processors and the calculation is concurrently done in each subdomain with interprocessor communications. Experimental pe rformance tests using three different styles of parallel computers ach ieved a fairly good speed up compared with conventional computation on a single processor: maximum speed-up rate of 26 using 32 processors o f a Thinking Machine CM-5 parallel computer, 1.6 using a Digital Equip ment DEC-Alpha two-CPU workstation, and 4.6 using a cluster of eight S un Microsystems SPARC-Station 10 (SPARC-10) workstations connected by an Ethernet. The result of this test agrees well with the performance theoretically predicted for each system. To demonstrate the feasibilit y of our parallel algorithm, we show three examples: 3-D acoustic and elastic modeling of fault-zone trapped waves and the calculation of el astic wave propagation in a 3-D syncline model.