MannekenPix (MPX)

MannekenPix or MPX (Aldersons, 2004) is an advanced single-trace automatic picking system for first P-wave arrivals recorded at local, regional and teleseismic distances. The program works in guided mode. It searches for a valid arrival around the time of a manual routine pick or around the time of a predicted value. If even a predicted value is not available because the event has not yet been located, MPX can also search for an arrival around the trigger time of a network detection algorithm.

MPX is a turn-key solution that does not require much tuning from an experienced user before a true production mode can be reached. The first benefit that can be expected from MPX is picking accuracy. Most automatic picks produced by the program are comparable to those of a good human analyst. MPX includes also a weighting mechanism rigorously calibrated on Reference picks and weights provided by the user. On unseen data, the weighting engine applies the knowledge gained during the calibration to mark every picked arrival with a quality label. The weighting mechanism of MPX attempts to predict the same uncertainties as those that would be estimated by a human analyst. As such, it acts as an extension of the manual approach and not as a totally independent method possibly in conflict with the legacy.

In the first step of MPX, the signal-to-noise ratio of the P-wavetrain is increased by an automatic and adaptive high-fidelity Wiener filter. The picking is performed in the second step by the versatile Baer-Kradolfer (Baer and Kradolfer, 1987) picking engine. If a valid pick has been found, variable delay corrections are applied in the third step in order to reduce the inherent lateness of the Baer-Kradolfer algorithm arrivals. In the fourth step, the weighting mechanism provides a statistical estimate of the picking uncertainty. For each data set, the weighting engine has to be calibrated first by a multiple discriminant analysis performed on at least 600 user-supplied reference picks and weights. The Reference picks and weights can be made using Sac2000 (Goldstein et al., 1999) under Unix, or with Visual Picker under MS-Windows. Since Visual Picker integrates the Wiener filter of MPX and visual tools for the determination of the Reference picking uncertainty, it is the recommended program for building the Reference set of picks and weights.

References

Aldersons, F. (2004) Toward a Three-Dimensional Crustal Structure of the Dead Sea region from Local Earthquake Tomography. Ph.D. thesis, Tel-Aviv University, pp. 123.
Baer, M., and Kradolfer, U. (1987) An automatic phase picker for local and teleseismic events. Bulletin of the Seismological Society of America , 77, 1437-1445.
Goldstein, P., Dodge, D., and Firpo, M. (1999) SAC2000: Signal processing and analysis tools for seismologists and engineers, UCRL-JC-135963, Invited contribution to the IASPEI International Handbook of Earthquake and Engineering Seismology.

Download MPX 1.7.9