Abstract
An adequate characterization of the temporal features of background seismicity, namely after removal of temporally and spatially clustered events (e.g. aftershocks), is a key element in several studies aimed at earthquake forecasting and seismic hazard assessment. In order to investigate the features of background seismicity component, we analyse the rate of background events, that is the rate of main/independent earthquakes as identified by Nearest Neighbour (NN) and Stochastic Declustering (SD) methods. The use of two different declustering methods, which are based on diverse statistical and physical assumptions, allows us to assess whether the identified features depend on the specific definition of background events. In this study, we carry out an in depth analysis of the time changes of background seismicity rate in Northeastern Italy, by means of continuous-time Hidden Markov Models, a stochastic tool that can be used to assess heterogeneity in the temporal pattern of seismicity rates. Specifically, we aim at understanding if the analysed time series can be better described by a homogeneous Poisson model, with unique constant rate, or by a switched Poisson model (i.e. linked to some systematic changes in earthquakes occurrence rates) or whether a basically different model is required. The analysis performed based on Markov modulated Poisson process, and according to Bayesian Information Criterion, shows that a switched Poisson process with three states is the best model describing the background rate identified by SD and NN approaches. The capability of adopted methodology in identifying seismicity rate changes, as well as the sensitivity of the method against the minimum magnitude threshold of analysis, have been verified by applying the method to synthetic catalogues with known properties, namely Poissonian time series with different rates prescribed in specific time intervals. The obtained results suggest that a Poisson model with multiple rates can be used to properly describe background seismicity in Northeastern Italy.
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References
Adelfio G, Chiodi M (2015) Alternated estimation in semiparametric space-time branching-type point processes with application to seismic catalogs. Stoch Environ Res Risk Assess 29(2):443–450. https://doi.org/10.1007/s00477-014-0873-8
Baiesi M, Paczuski M (2004) Scale-free networks of earthquakes and aftershocks. Phys Rev E 69:066106. https://doi.org/10.1103/PhysRevE.69.066106
Gardner JK, Knopoff L (1974) Is the sequence of earthquakes in Southern California, with aftershocks removed, Poissonian? Bull Seis Soc Am 64:1363–1367
Gulia L, Rinaldi AP, Tormann T, Vannucci G, Enescu B, Wiemer S (2018) The effect of a mainshock on the size distribution of the aftershocks. Geophys Res Lett 45:13277–13287
Gutenberg B, Richter CF (1944) Frequency of earthquakes in California. Bull Seismol Soc Am 34:185–188
Harte D (2017) HiddenMarkov: hidden Markov models. R package version 1.8–11. Statistics Research Associates, Wellington. https://www.statsresearch.co.nz/dsh/sslib/. Accessed 23 Sept 2019
Kagan YY (2017) Worldwide earthquake forecasts. Stoch Environ Res Risk Assess 31:1273–1290. https://doi.org/10.1007/s00477-016-1268-9
Kass RE, Raftery AE (1995) Bayes factors. J Am Stat Assoc 90:773–795
Kolev AA, Gordon JR (2018) Inference for ETAS models with non-Poissonian mainshock arrival times. Stat Comput. https://doi.org/10.1007/s11222-018-9845-z
Kumazawa T, Ogata Y, Tsuruoka H (2017) Measuring seismicity diversity and anomalies using point process models: case studies before and after the 2016 Kumamoto earthquakes in Kyushu, Japan. Earth Planets Space 69:169. https://doi.org/10.1186/s40623-017-0756-6
Li C, Song Z, Wang W (2019) Space–time inhomogeneous background intensity estimators for semi parametric space–time self-exciting point process models. Ann Inst Stat Math. https://doi.org/10.1007/s10463-019-00715-5
Lu S (2019) A Bayesian multiple changepoint model for marked poisson processes with applications to deep earthquakes. Stoch Environ Res Risk Assess 33:59–72. https://doi.org/10.1007/s00180-020-00956-6
Lombardi AM, Marzocchi W (2007) Evidence of clustering and nonstationarity in the time distribution of large worldwide earthquakes. J Geophys Res 112:B02303. https://doi.org/10.1029/2006JB004568
Lombardi AM, Cocco M, Marzocchi W (2010) On the increase of background seismicity rate during the 1997–1998 Umbria-Marche, Central Italy, sequence: apparent variation or fluid-driven triggering? Bull Seism Soc Am 100(3):1138–1152. https://doi.org/10.1785/0120090077
Lombardi AM (2015) Estimation of the parameters of ETAS models by simulated annealing. Sci Rep 5:8417. https://doi.org/10.1038/srep08417
Luen B, Stark PB (2012) Poisson tests of declustered catalogues. Geophys J Int 189(1):691–700. https://doi.org/10.1111/j.1365-246X.2012.05400.x
Nekrasova A, Kossobokov V, Peresan A, Aoudia A, Panza GF (2011) A multiscale application of the unified scaling law for earthquakes in the central Mediterranean area and alpine region. Pure Appl Geophys 168(1–2):297–327. https://doi.org/10.1007/s00024-010-0163-4
Ogata Y (1988) Statistical models for earthquake occurrences and residual analysis for point-processes. J Am Stat Assoc 83:9–27
Ogata Y (1998) Space-time point-process models for earthquake occurrences. Ann Inst Stat Math 50:379–402
Peresan A, Gentili S (2018) Seismic clusters analysis in Northeastern Italy by the nearest-neighbour approach. Phys Earth Plan Int 274:87–104. https://doi.org/10.1016/j.pepi.2017.11.007
Peresan A, Gentili S (2020) Identification and characterization of earthquake clusters: a comparative analysis for selected sequences in Italy and adjacent regions. Bollettino Di Geofisica Teorica E Applicata 61(1):57–80. https://doi.org/10.4430/bgta0249
Peruzza L, Garbin M, Snidarcig A, Sugan M, Urban S, Renner G, Romano MA (2015) Quarry blasts, underwater explosions and other dubious seismic events in NE Italy from 1977 till 2013. Boll Geof Teor Appl 56(4):437–459
Rydén T (1996) An EM algorithm for estimation in Markov-modulated Poisson processes. Comput Stat Data Anal 21:431–447
Slejko D, Neri G, Orozova I, Renner G, Wyss M (1999) Stress field in Friuli (NE Italy) from fault plane solutions of activity following the 1976 main shock. Bull Seism Soc Am 89:1037–1052
Touati S, Naylor M, Main IG, Christie M (2011) Masking of earthquake triggering behavior by a high background rate and implications for epidemic-type aftershock sequence inversions. J Geophys Res 116:B03304. https://doi.org/10.1029/2010JB007544
Touati S, Naylor M, Main I (2016) Detection of change points in underlying earthquake rates, with application to global mega-earthquakes. Geophys J Int 204:753–767. https://doi.org/10.1093/gji/ggv398
van Stiphout T, Zhuang J, Marsan D (2012) Seismicity declustering. Resour Stat Seism Anal. https://doi.org/10.5078/corssa52382934
Veen A, Schoenberg FP (2008) Estimation of space-time branching process models in seismology using an EM–type algorithm. J Am Stat Assoc 103(482):614–624. https://doi.org/10.1198/016214508000000148
Wyss M, Toya Y (2000) Is background seismicity produced at a stationary poissonian rate? Bull Seismol Soc Am 90:1174–1187. https://doi.org/10.1785/0119990158
Yip CF, Ng WL, Yau CY (2018) A hidden Markov model for earthquake prediction. Stoch Environ Res Risk Assess 32:1415. https://doi.org/10.1007/s00477-017-1457-1
Zaliapin I, Gabrielov A, Wong H, Keilis-Borok VI (2008) Clustering analysis of seismicity and aftershock identification. Phys Rev Lett 101:018501
Zaliapin I, Ben-Zion Y (2013) Earthquake clusters in southern California I: identification and stability. J Geophys Res 118(6):2847–2864
Zhuang J, Ogata Y, Vere-Jones D (2002) Stochastic declustering of space-time earthquake occurrences. J Am Stat Assoc 97:369–380. https://doi.org/10.1198/016214502760046925
Zhuang J, Chang CP, Ogata Y, Chen YI (2005) A study on the background and clustering seismicity in the Taiwan region by using a point process model. J Geophys Res 110:B05S18. https://doi.org/10.1029/2004JB003157
Zhuang J, Ogata Y, Vere-Jones D (2004) Analyzing earthquake clustering features by using stochastic reconstruction. J Geophys Res 109(B5):B05301. https://doi.org/10.1029/2003JB002879
Zhuang J (2006) Second-order residual analysis of spatiotemporal point processes and applications in model evaluation. J J R Stat Soc Ser B Stat Methodol 68(4):635–653. https://doi.org/10.1111/j.1467-9868.2006.00559.x
Acknowledgements
We are grateful to Ilya Zaliapin and Jiancang Zhuang for providing the codes for catalogue declustering. This study was possible thanks to Ph.D. training financial support from University of Sciences and Technology Houari Boumediene (USTHB), Algiers, Algeria. The research also benefited from financial support by Protezione Civile della Regione Autonoma Friuli-Venezia Giulia and Regione Veneto, and by the National grant MIUR, PRIN-2015 program, Prot. 20157PRZC4: "Complex space–time modeling and functional analysis for probabilistic forecast of seismic events".
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Benali, A., Peresan, A., Varini, E. et al. Modelling background seismicity components identified by nearest neighbour and stochastic declustering approaches: the case of Northeastern Italy. Stoch Environ Res Risk Assess 34, 775–791 (2020). https://doi.org/10.1007/s00477-020-01798-w
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DOI: https://doi.org/10.1007/s00477-020-01798-w