Seismo-volcano source localization with triaxial broad-band seismic array

SUMMARY Seismo-volcano source localization is essential to improve our understanding of eruptive dynamics and of magmatic systems. The lack of clear seismic wave phases prohibits the use of classical location methods. Seismic antennas composed of one-component (1C) seismometers provide a good estimate of the backazimuth of the wavefield. The depth estimation, on the other hand, is difficult or impossible to determine. As in classical seismology, the use of three-component (3C) seismometers is now common in volcano studies. To determine the source location parameters (backazimuth and depth), we extend the 1C seismic antenna approach to 3Cs. This paper discusses a high-resolution location method using a 3C array survey (3C-MUSIC algorithm) with data from two seismic antennas installed on an andesitic volcano in Peru (Ubinas volcano). One of the main scientific questions related to the eruptive process of Ubinas volcano is the relationship between the magmatic explosions and long-period (LP) swarms. After introducing the 3C array theory, we evaluate the robustness of the location method on a full wavefield 3-D synthetic data set generated using a digital elevation model of Ubinas volcano and an homogeneous velocity model. Results show that the backazimuth determined using the 3C array has a smaller error than a 1C array. Only the 3C method allows the recovery of the source depths. Finally, we applied the 3C approach to two seismic events recorded in 2009. Crossing the estimated backazimuth and incidence angles, we find sources located 1000 ± 660 m and 3000 ± 730 m below the bottom of the active crater for the explosion and the LP event, respectively. Therefore, extending 1C arrays to 3C arrays in volcano monitoring allows a more accurate determination of the source epicentre and now an estimate for the depth.

[1]  B. Chouet,et al.  Performance of the Radial Semblance Method for the Location of Very Long Period Volcanic Signals , 2003 .

[2]  M. Alidibirov,et al.  Three fragmentation mechanisms for highly viscous magma under rapid decompression , 2000 .

[3]  Patrick Gounon,et al.  Wideband spectral matrix filtering for multicomponent sensors array , 2005, Signal Process..

[4]  Christopher J. Bean,et al.  A 3D discrete numerical elastic lattice method for seismic wave propagation in heterogeneous media with topography , 2004 .

[5]  D. Dingwell,et al.  Repeated fracture and healing of silicic magma generate flow banding and earthquakes , 2003 .

[6]  D. Patanè,et al.  Moment‐tensor inversion of LP events recorded on Etna in 2004 using constraints obtained from wave simulation tests , 2007 .

[7]  Nicolas Le Bihan,et al.  Quaternion-MUSIC for vector-sensor array processing , 2006, IEEE Transactions on Signal Processing.

[8]  R. O. Schmidt,et al.  Multiple emitter location and signal Parameter estimation , 1986 .

[9]  T. Ohminato,et al.  Aso94: Aso seismic observation with broadband instruments , 2000 .

[10]  W. Hildreth.  New perspectives on the eruption of 1912 in the valley of ten thousand smokes, Katmai National Park, Alaska , 1987 .

[11]  K. Aki,et al.  Location of seismic events and eruptive fissures on the Piton de la Fournaise volcano using seismic amplitudes , 2003 .

[12]  Nicolas Le Bihan,et al.  Vector-Sensor MUSIC for Polarized Seismic Sources Localization , 2005, EURASIP J. Adv. Signal Process..

[13]  O. Lengliné,et al.  Short term forecasting of explosions at Ubinas volcano, Perú , 2011 .

[14]  Gilberto Saccorotti,et al.  Time reverse location of seismic long-period events recorded on Mt Etna , 2011 .

[15]  B. Chouet,et al.  Spatial extent of a hydrothermal system at Kilauea Volcano, Hawaii, determined from array analyses of shallow long-period seismicity 2. Results , 2001 .

[16]  O. Melnik,et al.  Dynamics of magma ascent and lava extrusion at Soufrière Hills Volcano, Montserrat , 2002, Geological Society, London, Memoirs.

[17]  P. Papale.  Strain-induced magma fragmentation in explosive eruptions , 1999, Nature.

[18]  B. Valette,et al.  Locating sources of volcanic tremor and emergent events by seismic triangulation: Application to Arenal volcano, Costa Rica , 2002 .

[19]  P. Francis,et al.  Volcanoes of the Central Andes , 1991 .

[20]  G. Saccorotti,et al.  Continuous tracking of volcanic tremor at Mount Etna, Italy , 2007 .

[21]  D. Patanè,et al.  Source geometry from exceptionally high resolution long period event observations at Mt Etna during the 2008 eruption , 2009, 1001.2922.

[22]  J. Neuberg,et al.  Effects of volcano topography on seismic broad‐band waveforms , 2000 .

[23]  Jerome Mars,et al.  Advanced signal processing tools for dispersive waves , 2004 .

[24]  K. T. Wong,et al.  Closed-form direction finding and polarization estimation with arbitrarily spaced electromagnetic vector-sensors at unknown locations , 2000 .

[25]  G. Bienvenu,et al.  Optimality of high resolution array processing using the eigensystem approach , 1983 .

[26]  Jean Virieux,et al.  An efficient algorithm for double‐difference tomography and location in heterogeneous media, with an application to the Kilauea volcano , 2005 .

[27]  M. Ruiz,et al.  Ascending seismic source during an explosive eruption at Tungurahua volcano, Ecuador , 2011 .

[28]  Jérôme I. Mars,et al.  New multicomponent filters for geophysical data processing , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[29]  M. Alidibirov,et al.  Magma fragmentation by rapid decompression , 1996, Nature.

[30]  C. Fischione,et al.  Performances of the UNDERground SEISmic array for the analysis of seismicity in Central Italy , 2006 .

[31]  Locating volcano-seismic signals in the presence of rough topography: wave simulations on Arenal volcano, Costa Rica , 2009 .

[32]  Bernard A. Chouet,et al.  Source mechanism of Vulcanian degassing at Popocatépetl Volcano, Mexico, determined from waveform inversions of very long period signals , 2005 .

[33]  Gilberto Saccorotti,et al.  Quantitative analysis of the tremor wavefield at Etna Volcano, Italy , 2002 .

[34]  Gilberto Saccorotti,et al.  A probabilistic approach to the inversion of data from a seismic array and its application to volcanic signals , 2000 .

[35]  B. Voight,et al.  Episodes of cyclic Vulcanian explosive activity with fountain collapse at Soufrière Hills Volcano, Montserrat , 2002, Geological Society, London, Memoirs.

[36]  Jérôme I. Mars,et al.  Vector-Sensor Array Processing for Polarization Parameters and DOA Estimation , 2010, EURASIP J. Adv. Signal Process..

[37]  Sharon Kedar,et al.  Waveform inversion of very long period impulsive signals associated with magmatic injection beneath , 1998 .

[38]  Gilberto Saccorotti,et al.  Probabilistic source location of explosion quakes at Stromboli volcano estimated with double array data , 2004 .

[39]  H. Itoc,et al.  Aso 94 : Aso seismic observation with broadband instruments , 2000 .

[40]  P. Palacios,et al.  Seismic tracking of lahars using tremor signals , 2009 .

[41]  B. Chouet,et al.  Mapping the Sources of the Seismic Wave Field at Kilauea Volcano, Hawaii, Using Data Recorded on Multiple Seismic Antennas , 2002 .

[42]  C. Bean,et al.  Influence of near-surface volcanic structure on long-period seismic signals and on moment tensor inversions : Simulated examples from Mount Etna , 2008 .

[43]  Nicolas Le Bihan,et al.  High Resolution Vector-Sensor Array Processing Based on Biquaternions , 2006, 2006 IEEE International Conference on Acoustics Speech and Signal Processing Proceedings.

[44]  Bernard A. Chouet,et al.  Long-period volcano seismicity: its source and use in eruption forecasting , 1996, Nature.

[45]  D. Patanè,et al.  Source mechanism of long-period events recorded by a high-density seismic network during the 2008 eruption on Mount Etna , 2010, 1011.1085.

[46]  Javier Almendros,et al.  Quantitative analysis of seismic wave propagation anomalies in azimuth and apparent slowness at Deception Island volcano (Antarctica) using seismic arrays , 2011 .

[47]  D. Dingwell,et al.  The trigger mechanism of low-frequency earthquakes on Montserrat , 2006 .

[48]  D. Dingwell,et al.  Fault textures in volcanic conduits: evidence for seismic trigger mechanisms during silicic eruptions , 2005 .