Automated identification, location, and volume estimation of rockfalls at Piton de la Fournaise volcano

Since the collapse of the Dolomieu crater floor at Piton de la Fournaise Volcano (la Reunion) in 2007, hundreds of seismic signals generated by rockfalls have been recorded daily at the Observatoire Volcanologique du Piton de la Fournaise (OVPF). To study rockfall activity over a long period of time, automated methods are required to process the available continuous seismic records. We present a set of automated methods designed to identify, locate, and estimate the volume of rockfalls from their seismic signals. The method used to automatically discriminate seismic signals generated by rockfalls from other common events recorded at OVPF is based on fuzzy sets and has a success rate of 92%. A kurtosis-based automated picking method makes it possible to precisely pick the onset time and the final time of the rockfall-generated seismic signals. We present methods to determine rockfall locations based on these accurate pickings and a surface-wave propagation model computed for each station using a Fast Marching Method. These methods have successfully located directly observed rockfalls with an accuracy of about 100 m. They also make it possible to compute the seismic energy generated by rockfalls, which is then used to retrieve their volume. The methods developed were applied to a data set of 12,422 rockfalls that occurred over a period extending from the collapse of the Dolomieu crater floor in April 2007 to the end of the UnderVolc project in May 2011 to identify the most hazardous areas of the Piton de la Fournaise volcano summit.

[1]  M. Leonard,et al.  Comparison of Manual and Automatic Onset Time Picking , 2000 .

[2]  Stephen R. McNutt,et al.  VOLCANIC SEISMOLOGY , 2005 .

[3]  N. Maeda.  A Method for Reading and Checking Phase Time in Auto-Processing System of Seismic Wave Data , 1985 .

[4]  Manfred Baer,et al.  An automatic phase picker for local and teleseismic events , 1987 .

[5]  R. V. Allen,et al.  Automatic phase pickers: Their present use and future prospects , 1982 .

[6]  J. Sethian,et al.  3-D traveltime computation using the fast marching method , 1999 .

[7]  K. Aki,et al.  Frequency-dependent site amplification factors using the S-wave coda for the island of Hawaii , 1992 .

[8]  Haresh C. Shah,et al.  Fuzzy information processing in seismic hazard analysis and decision making , 1987 .

[9]  Stavros M. Panas,et al.  PAI-S/K: A robust automatic seismic P phase arrival identification scheme , 2002, IEEE Trans. Geosci. Remote. Sens..

[10]  Vi︠a︡cheslav Moiseevich Zobin.  Introduction to Volcanic Seismology , 2003 .

[11]  Clifford H. Thurber,et al.  Automatic P-Wave Arrival Detection and Picking with Multiscale Wavelet Analysis for Single-Component Recordings , 2003 .

[12]  Aline Peltier,et al.  First Results from the UnderVolc High Resolution Seismic and GPS Network Deployed on Piton de la Fournaise Volcano , 2012 .

[13]  J. Martí,et al.  April 2007 collapse of Piton de la Fournaise: A new example of caldera formation , 2007 .

[14]  Michel Campillo,et al.  3‐D surface wave tomography of the Piton de la Fournaise volcano using seismic noise correlations , 2007 .

[15]  B. Voight,et al.  Mechanisms of lava dome instability and generation of rockfalls and pyroclastic flows at Soufrière Hills Volcano, Montserrat , 2002, Geological Society, London, Memoirs.

[16]  Gilles Grandjean,et al.  Monitoring water flow in a clay-shale hillslope from geophysical data fusion based on a fuzzy logic approach , 2009 .

[17]  Gilles Grandjean,et al.  Slope instabilities in Dolomieu crater, Réunion Island: From seismic signals to rockfall characteristics , 2011 .

[18]  J. Deparis.  Etude des éboulements rocheux par méthodes géophysiques , 2007 .

[19]  Paul G. Richards,et al.  Quantitative Seismology: Theory and Methods , 1980 .

[20]  J. Sethian,et al.  traveltime computation using the fast marching method , 1999 .

[21]  H. Kao,et al.  Hypocentre determination offshore of eastern Taiwan using the Maximum Intersection method , 2004 .

[22]  Emma Suriñach,et al.  Rockfall induced seismic signals: case study in Montserrat, Catalonia , 2008 .

[23]  F. Glangeaud,et al.  Three-component signal recognition using time, time-frequency, and polarization information-application to seismic detection of avalanches , 1998, IEEE Trans. Signal Process..

[24]  B. Voight,et al.  The eruption of Soufrière Hills Volcano, Montserrat from 1995 to 1999 , 2002 .

[25]  A Ratdomopurbo,et al.  An overview of the seismicity of Merapi volcano (Java, Indonesia), 1983–1994 , 2000 .

[26]  Simon Loew,et al.  Characterization of alpine rockslides using statistical analysis of seismic signals , 2011 .

[27]  F. Massin,et al.  The April 2007 eruption and the Dolomieu crater collapse, two major events at Piton de la Fournaise (La Réunion Island, Indian Ocean) , 2009 .

[28]  M. Haney.  Location and Mechanism of Very Long Period Tremor During the 2008 Eruption of Okmok Volcano from Interstation Arrival Times , 2010 .

[29]  J A Sethian,et al.  A fast marching level set method for monotonically advancing fronts. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[30]  Alberto Michelini,et al.  Continuous Kurtosis‐Based Migration for Seismic Event Detection and Location, with Application to Piton de la Fournaise Volcano, La Réunion , 2014 .

[31]  Haijiang Zhang,et al.  Locating nonvolcanic tremors beneath the San Andreas Fault using a station‐pair double‐difference location method , 2010 .

[32]  J. M. Vilaplana,et al.  Seismic detection and characterization of landslides and other mass movements , 2005 .

[33]  H. Langer,et al.  Automatic classification and a-posteriori analysis of seismic event identification at Soufriere Hills volcano, Montserrat , 2006 .

[34]  M. Leonard,et al.  Multi-component autoregressive techniques for the analysis of seismograms , 1999 .

[35]  G. Zandt,et al.  Seismic detection and characterization of the Altiplano-Puna magma body , 2003 .

[36]  S. Crampin.  Higher modes of seismic surface waves: Second Rayleigh mode energy , 1965 .

[37]  Stéphane Garambois,et al.  Seismic monitoring of Séchilienne rockslide (French Alps): Analysis of seismic signals and their correlation with rainfalls , 2010 .

[38]  Gilles Grandjean,et al.  JaTS: a fully portable seismic tomography software based on Fresnel wavepaths and a probabilistic reconstruction approach , 2004, Comput. Geosci..

[39]  J. Neuberg,et al.  The relationship between degassing and rockfall signals at Soufrière Hills Volcano, Montserrat , 2002, Geological Society, London, Memoirs.

[40]  Matt A. King,et al.  Journal of Geophysical Research: Earth Surface , 2015 .

[41]  Anatoli L. Levshin,et al.  Seismic surface waves in a laterally inhomogeneous earth , 1989 .

[42]  Anne Mangeney,et al.  An Automatic Kurtosis‐Based P ‐ and S ‐Phase Picker Designed for Local Seismic Networks , 2014 .

[43]  Lotfi A. Zadeh,et al.  Fuzzy Sets , 1996, Inf. Control..

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

[45]  Laurent Baillet,et al.  Analysis of Rock-Fall and Rock-Fall Avalanche Seismograms in the French Alps , 2008 .

[46]  J. Malet,et al.  Characterizing landslides through geophysical data fusion: Example of the La Valette landslide (France) , 2012 .

[47]  Reinoud Sleeman,et al.  Robust automatic P-phase picking: an on-line implementation in the analysis of broadband seismogram recordings , 1999 .