Definition of Seismic Signal Parameters by Particle-Motion Processing

Theoretical and observed particle motion of P and Lg waves indicates that a successful definition of signal parameters can be made by particle-motion algorithms. Tests on many Pn, Pg, and P phases recorded at OB2NV and RKON reveal that back azimuths can be estimated almost always to within or - 20 deg at SN 5 and quite often to this precision at SN 5. Incidence angles are not sufficiently resolved to reliably discriminate regional from teleseismic P waves though. Lg waves recorded at these same stations yielded better back azimuth estimates at equivalent SN ratios than P waves. The azimuth estimates made by particle-motion processing showed no deterioration with increasing frequency to 10 Hz, provided SN remained high. An experiment using 3-component data at ANMO, BOCO, and BCAO resulted in only mild success for characterizing wave type and measuring the signal parameters with particle-motion processing more complex algorithms and additional kinds of processing will be required to identify regional phases routinely.