IEEE Signal Processing - March 2018 - 29

volcanic observatories. Semisupervised learning methods can
be considered, and some studies have used HMM for this purpose [40]. The use of several sensors and of hierarchical models
could also be considered to improve the robustness of the detection and classification results. Finally, alternative approaches to
classify known data without any a priori knowledge on classes
and detect new classes pose a challenging prospect that would
allow the monitoring of a volcano that has previously not been
examined. The use of unsupervised learning methods can thus
be considered.

Acknowledgments
This work has been supported by a grant from Labex
OSUG@2020 (Investissements d'avenir-ANR10 LABX56)
and DGA/MRIS. GIPSA-Lab SIGMAPHY is part of Labex
OSUG@2020 (ANR10 LABX56).

Authors
Marielle Malfante (marielle.malfante@gipsa-lab.fr) received her
M.Sc. degree in signal processing in 2015 from Grenoble Institute
of Technology, France. She is currently pursuing her Ph.D. degree
in automatic classification of natural signals for environmental
monitoring. She received the First Prize Best Student Paper
Award in animal bioacoustics at the Salt Lake City meeting of the
Acoustical Society of America in 2016.
Mauro Dalla Mura (mauro.dalla-mura@gipsa-lab.fr)
received the laurea (B.E.) and laurea specialistica (M.E.) degrees
in telecommunication engineering from the University of Trento,
Italy, in 2005 and 2007, respectively. In 2011, he obtained a joint
Ph.D. degree in information and communication technologies
(telecommunications area) from the University of Trento, Italy,
and in electrical and computer engineering from the University
of Iceland. He is currently an assistant professor at the Grenoble
Institute of Technology, France. He was the recipient of the IEEE
Geoscience and Remote Sensing Society (GRSS) Second Prize
in the Student Paper Competition of the 2011 IEEE International
Geoscience and Remote Sensing Symposium (IGARSS) 2011
and corecipient of the Best Paper Award of International Journal
of Image and Data Fusion for the year 2012-2013 and the
Symposium Paper Award for the IEEE IGARSS 2014. He has
been the president of the IEEE GRSS French Chapter since
2016. He has been on the editorial board of IEEE Journal of
Selected Topics in Applied Earth Observations and Remote
Sensing since 2016.
Jérôme I. Mars ( jerome.mars@gipsa-lab.fr) received his
master's degree in mechanics and geophysics from University
Joseph Fourier (now known as the University Grenoble Alpes),
Grenoble, France, in 1986 and his Ph.D. degree in signal processing in 1988 from the Institut National Polytechnique de
Grenoble. He is a professor with the Grenoble Institute of Technology, France. He is currently the head of the Grenoble Images
Speech Signals and Automatics Laboratory. His research interests cover statistical signal processing and source separation. His
latest research focus is mainly in the field of wave propagation
(underwater acoustics, geosciences, and tomography). He is a
Member of the IEEE.

Jean-Philippe Métaxian ( jean-philippe.metaxian@ird.fr)
received his master's degree in mechanics and geophysics in 1990
from University Joseph Fourier (now known as the University
Grenoble Alpes), Grenoble, France, and his Ph.D. degree in geophysics in 1994 from the Université de Savoie, Chambéry,
France. He has been a researcher at the Institut de Recherche
pour le Développement since 1994. He is part of the geophysics
of volcanoes team at the Institut des Sciences de la Terre
Laboratory and the seismology team at the Institut de Physique
du Globe de Paris. His research interests include volcano seismology, and his latest focus is in the fields of volcano structure and
the study of eruptive processes by using technics of dense and
short aperture seismic arrays.
Orlando Macedo (omacedo@igp.gob.pe) received his master's degree in geophysics in 1983 from University Paris 7,
France, and his Ph.D. degree in geodynamics and physics of the
earth from University Orsay Paris 11, France, in 1993. He has
been a researcher at the Instituto Geofisico del Peru since 1986,
where he was the director of the Department of Volcanology
from 1986 to 2014. He is the director of the observatory of volcanology of South Peru in Arequipa. He has been a professor of
geophysics at the University Nacional San Agustin de Arequipa,
Peru, since 2003. His research interests include geophysics, volcano seismology, and geophysical monitoring of active volcanoes in Peru.
Adolfo Inza (adolfo.inza@igp.gob.pe) received his bachelor's degree in science in electronics at the Universidad
Nacional de Ingeneria, Lima, Peru, in 1992 and his Ph.D. degree
in geophysics at Université Grenoble Alpes, France, in 2013.
He has been an electronics engineer at Instituto Geofisico del
Peru (IGP) since 1992 and a researcher at IGP since 2013. His
research interests include seismology, geophysics, volcano
seismology, and geophysical monitoring of active volcanoes
in Peru.

References

[1] "International strategy for disaster reduction," 70th U.N. General Assembly,
UN-ISDR, no. 20c, New York, Dec. 2015, p. 22.
[2] J. C. Lahr, B. A. Chouet, C. D. Stephens, J. A. Power, and R. A. Page, "Earthquake
classification, location, and error analysis in a volcanic environment: Implications for
the magmatic system of the 1989-1990 eruptions at Redoubt volcano, Alaska," J.
Volcanol. Geotherm. Res., vol. 62, no. 1-4, pp. 137-151, 1994.
[3] K. Aki, M. Fehler, and S. Das, "Source mechanism of volcanic tremor: Fluid-driven
crack models and their application to the 1963 Kilauea eruption," J. Volcanol.
Geotherm. Res., vol. 2, no. 3, pp. 259-287, 1977.
[4] B. Chouet, "Resonance of a fluid-driven crack: Radiation properties and implications for the source of long-period events and harmonic tremor," J. Geophys. Res. Solid
Earth, vol. 93, no. B5, pp. 4375-4400, 1988.
[5] J. Neuberg, R. Luckett, B. Baptie, and K. Olsen, "Models of tremor and low-frequency earthquake swarms on Montserrat," J. Volcanol. Geotherm. Res. vol. 101, no.
1, pp. 83-104, 2000.
[6] E. Del Pezzo, F. Bianco, and I. Borgna, "Magnitude scale for lp events: A quantification scheme for volcanic quakes," Geophys. J. Int., vol. 194, no. 2, pp. 911-919,
2013.
[7] B. A. Chouet and R. S. Matoza, "A multi-decadal view of seismic methods for
detecting precursors of magma movement and eruption," J. Volcanol. Geotherm. Res.,
vol. 252, suppl. C, pp. 108-175, 2013.
[8] B. A. Chouet, "Long-period volcano seismicity: Its source and use in eruption forecasting," Nature, vol. 380, no. 6572, pp. 309-316, Mar. 1996.
[9] S. McNutt, "Volcanic tremor," Encyclopedia Earth Syst. Sci., vol. 4, pp. 417-425,
1992.

IEEE Signal Processing Magazine

March 2018

Table of Contents for the Digital Edition of IEEE Signal Processing - March 2018