TY  - JOUR
A1  - Hammer, Conny
A1  - Ohrnberger, Matthias
A1  - Faeh, Donat
T1  - Classifying seismic waveforms from scratch: a case study in the alpine environment
JF  - Geophysical journal international
N2  - Nowadays, an increasing amount of seismic data is collected by daily observatory routines. The basic step for successfully analyzing those data is the correct detection of various event types. However, the visually scanning process is a time-consuming task. Applying standard techniques for detection like the STA/LTAtrigger still requires the manual control for classification. Here, we present a useful alternative. The incoming data stream is scanned automatically for events of interest. A stochastic classifier, called hidden Markov model, is learned for each class of interest enabling the recognition of highly variable waveforms. In contrast to other automatic techniques as neural networks or support vector machines the algorithm allows to start the classification from scratch as soon as interesting events are identified. Neither the tedious process of collecting training samples nor a time-consuming configuration of the classifier is required. An approach originally introduced for the volcanic task force action allows to learn classifier properties from a single waveform example and some hours of background recording. Besides a reduction of required workload this also enables to detect very rare events. Especially the latter feature provides a milestone point for the use of seismic devices in alpine warning systems. Furthermore, the system offers the opportunity to flag new signal classes that have not been defined before. We demonstrate the application of the classification system using a data set from the Swiss Seismological Survey achieving very high recognition rates. In detail we document all refinements of the classifier providing a step-by-step guide for the fast set up of a well-working classification system.
KW  - Time series analysis
KW  - Neural networks, fuzzy logic
KW  - Seismic monitoring and test-ban treaty verification
KW  - Early warning
KW  - Probability distributions
Y1  - 2013
U6  - https://doi.org/10.1093/gji/ggs036
SN  - 0956-540X
SN  - 1365-246X
VL  - 192
IS  - 1
SP  - 425
EP  - 439
PB  - Oxford Univ. Press
CY  - Oxford
ER  -