The 2015 Illapel earthquake, central Chile: A type case for a characteristic earthquake?

Tilmann, Frederik; Zhang, Y.; Moreno, M.; Saul, Joachim; Eckelmann, Felix; Palo, M.; Deng, Zhiguo; Babeyko, Andrey; Chen, Kejie; Báez, Juan Carlos; Schurr, Bernd; Wang, R.; Dahm, Torsten

doi:10.1002/2015gl066963

Cited by 133 publications

(177 citation statements)

References 47 publications

(72 reference statements)

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“…The new geodetic measurements provide us with a wealth of information about the present day stress build-up and release in dependence of strike and depth (e.g. Schurr et al 2014;Tilmann et al 2016;Frank et al 2017;Melnick et al 2017;Poli et al 2017). In principle, the resulting detailed slip distributions offer the possibility for 2-D studies which could overcome some problems of our simple 1-D approach and likely lead to more positive test results.…”

Section: Discussionmentioning

confidence: 99%

“…The rupture length and location for recent strong events were taken from Barrientos & Ward (1990) for the M9.6 1960 Valdivia earthquake, Delouis et al (1997) for the M7.6 1987 earthquake near Antofagasta, Ruegg et al (1996) for the M8.0 1995 Antofagasta earthquake, Pritchard & Simons (2006) for the M9.6 1960 Valdivia earthquake, Chlieh et al (2011) for the M8.4 2001 Arequipa earthquake, the rupture plane of which extends well into our area of investigation, Schurr et al (2014) for the M7.9 2007 Tocopilla earthquake, Yue et al (2014) for the M8.8 2010 Maule earthquake, Geersen et al (2015) and Schurr et al (2014) for the M8.1 2014 Iquique earthquake, and Tilmann et al (2016) for the M8.2 2015 Illapel earthquake. In the case that the rupture length is not constrained by observations, we estimate rupture lengths from the scaling relation of Blaser et al (2010) for dip-slip inter-plate earthquakes.…”

Section: Data Preparationmentioning

confidence: 99%

“…From 1900 to 2013 we use the ISC-GEM data (Storchak et al 2013). Later earthquakes are included by hand, that is, for the 2014 Iquique earthquake using Geersen et al (2015) and Schurr et al (2014) and for the 2015 Illapel earthquake using Tilmann et al (2016). We confine our study to earthquakes with intensity of 8 and higher or any magnitude value being equal or higher than 6.5.…”

Section: Data Preparationmentioning

confidence: 99%

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Testing stress shadowing effects at the South American subduction zone

Roth¹,

Dahm²,

Hainzl³

2017

Geophysical Journal International

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S U M M A R YThe seismic gap hypothesis assumes that a characteristic earthquake is followed by a long period with a reduced occurrence probability for the next large event on the same fault segment, as a consequence of the induced stress shadow. The gap model is commonly accepted by geologists and is often used for time-dependent seismic hazard estimations. However, systematic and rigorous tests to verify the seismic gap model have often failed so far, which might be partially related to limited data and too tight model assumptions. In this study, we relax the assumption of a characteristic size and location of repeating earthquakes and analyse one of the best available data sets, namely the historical record of major earthquakes along a 3000 km long linear segment of the South American subduction zone. To test whether a stress shadow effect is observable, we compiled a comprehensive catalogue of mega-thrust earthquakes along this plate boundary from 1520 to 2015 containing 174 earthquakes with M w > 6.5. In our new testing approach, we analyse the time span between an earthquake and the last event that ruptured the epicentre location, where we consider the impact of the uncertainties of epicentres and rupture extensions. Assuming uniform boundary conditions along the trench, we compare the distribution of these recurrence times with simple recurrence models. We find that the distribution is in all cases almost exponentially distributed corresponding to a random (Poissonian) process; despite some tendencies for clustering of the M w ≥ 7 events and a weak quasi-periodicity of the M w ≥ 8 earthquakes, respectively. To verify whether the absence of a clear stress shadow signal is related to physical assumptions or data uncertainties, we perform simulations of a physics-based stochastic earthquake model considering rate and state-dependent earthquake nucleation, which are adapted to the observations with regard to the number of events, spatial extend, size distribution and involved uncertainties. Our simulations show that the catalogue uncertainties lead to a significant blurring of the theoretically peaked distribution, but the distribution would be still distinguishable from the observed one for M w ≥ 7 events. However, considering the stress transfer to adjacent fault segments and heterogeneous instead of constant stress drop within the rupture zone can explain the observed recurrence time distribution. We conclude that simplified recurrence models, ignoring the complexity of the underlying physical process, cannot be applied for forecasting the M w ≥ 7 earthquake occurrence at this plate boundary.

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Section: Discussionmentioning

confidence: 99%

Section: Data Preparationmentioning

confidence: 99%

Section: Data Preparationmentioning

confidence: 99%

See 1 more Smart Citation

Testing stress shadowing effects at the South American subduction zone

Roth¹,

Dahm²,

Hainzl³

2017

Geophysical Journal International

Self Cite

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“…2). All aftershock clusters coincide with the areas of positive Coulomb stress change recently determined by Tilmann et al (2016) with maximum values up to 0.2 MPa (clusters A and B). Stress transfer from the coseismic rupture during the 2015 Illapel earthquake therefore likely triggered the development of aftershock clusters A and B at ∼32 • S-32.3 • S and possibly also clusters C and D at ∼33 • S-33.3 • S. Aftershocks in the south started ∼24 hr (clusters A and B) and 72 hr (clusters C and D) after the main shock (Fig.…”

Section: R E S U Lt S a N D Discussionmentioning

confidence: 99%

Aftershock seismicity and tectonic setting of the 2015 September 16 Mw 8.3 Illapel earthquake, Central Chile

Lange

Geersen

Barrientos

et al. 2016

Geophysical Journal International

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Powerful subduction zone earthquakes rupture thousands of square kilometres along continental margins but at certain locations earthquake rupture terminates. To date, detailed knowledge of the parameters that govern seismic rupture and aftershocks is still incomplete. On 2015 September 16, the Mw 8.3 Illapel earthquake ruptured a 200 km long stretch of the Central Chilean subduction zone, triggering a tsunami and causing significant damage. Here, we analyse the temporal and spatial pattern of the coseismic rupture and aftershocks in relation to the tectonic setting in the earthquake area. Aftershocks cluster around the area of maximum coseismic slip, in particular in lateral and downdip direction. During the first 24 hr after the main shock, aftershocks migrated in both lateral directions with velocities of approximately 2.5 and 5 km hr−1. At the southern rupture boundary, aftershocks cluster around individual subducted seamounts that are related to the downthrusting Juan Fernández Ridge. In the northern part of the rupture area, aftershocks separate into an upper cluster (above 25 km depth) and a lower cluster (below 35 km depth). This dual seismic–aseismic transition in downdip direction is also observed in the interseismic period suggesting that it may represent a persistent feature for the Central Chilean subduction zone.

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“…Geodetic methods are widely used to infer the pattern of locked areas during the interseismic stage. These studies show that the pattern of interseismic coupling on subduction megathrusts is generally heterogeneous [e.g., Chlieh et al, 2008;Moreno et al, 2010], and coupled areas are tentatively interpreted as asperities failing during earthquakes [e.g., Moreno et al, 2010, Schurr et al, 2014, Tilmann et al, 2016. However, the physical conditions that lead to simultaneous rupture of neighboring highly stressed patches and consequent triggering of a megathrust earthquake remain debated.…”

Section: Introductionmentioning

confidence: 99%

Control of asperities size and spacing on seismic behavior of subduction megathrusts

Corbi

Funiciello

Brizzi

et al. 2017

Geophysical Research Letters

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The majority of the largest subduction megathrust earthquakes share the common characteristic of rupturing more than one asperity along strike of the margin. Understanding the factors that control coseismic failure of multiple asperities, and thus maximum magnitude, is central for seismic hazard assessment. To investigate the role of asperities size and spacing on maximum magnitude, seismicity rate, and percentage of synchronized ruptures, we use analog models simulating along‐strike rupture behavior of megathrust earthquakes. We found negative correlations between the barrier‐to‐asperity length ratio Db/Da and maximum magnitude and seismicity rate. Db/Da also controls the process of asperities synchronization along the megathrust. A permanent barrier behavior is observed for Db/Da > 0.5. Comparing our experimental results to the Nankai Trough historical seismicity, we propose that the distribution of megathrust frictional heterogeneities likely explains the diversity of earthquakes which occurred there.

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The 2015 Illapel earthquake, central Chile: A type case for a characteristic earthquake?

Cited by 133 publications

References 47 publications

Testing stress shadowing effects at the South American subduction zone

Testing stress shadowing effects at the South American subduction zone

Aftershock seismicity and tectonic setting of the 2015 September 16 Mw 8.3 Illapel earthquake, Central Chile

Control of asperities size and spacing on seismic behavior of subduction megathrusts

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