Volcano-seismic Signal Detection and Classification Processing using Hidden Markov Models. Application to San Cristóbal Volcano, Nicaragua. - Ligdamis A. Gutiérrez; Jesús Ibáñez 003; Guillermo Cortés; Javier Ramírez 001; M. Carmen Benítez; Virginia Tenorio; Isaac Álvarez (IGARSS (4), 2009)