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Global map of the active subduction zones, where the 200 km trench segments have been ranked in terms of their predicted capability of generating a giant subduction zone earthquake with M W > 8.5. The segments have been ranked in terms of six subduction zone parameters: trench-normal overriding plate deformation rate (v OPD\ ), trench-normal trench velocity (v T\ ), subduction thrust dip angle (d ST ), subduction partitioning (v SP\ /v S\ ), subduction thrust curvature (C ST ) and trench curvature angle (a T ). For the lowest possible score (S = 0), the values of the six parameters of a particular trench segment are all outside the ranges observed for M W > 8.5 earthquakes (using the rupture zone dataset for ranges, see Fig. 3 and Table 2), implying a low risk of producing an M W > 8.5 earthquake. For the highest possible score (S = 6), all six values are inside the ranges, implying a high risk of producing an M W > 8.5 earthquake. Abbreviations for the subduction zone segments are explained in the figure caption of Fig. 1.
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The maximum earthquake magnitude recorded for subduction zone plate boundaries varies considerably on Earth, with some subduction zone segments producing giant subduction zone thrust earthquakes (e.g. Chile, Alaska, Sumatra–Andaman, Japan) and others producing relatively small earthquakes (e.g. Mariana, Scotia). Here we show how such variability mi...
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... we take the conceptual model developed in Section 5.4 for the three largest subduction zone earthquakes and apply it to other subduction zone regions shown in Fig. 9 with high scores, then sev- eral regions jump out due to their comparable tectonic setting. Table 4 Ranges for seven subduction zone parameters (200 km datasets) for four historic giant earthquakes (for entire rupture zone ...
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... M W > 8.5 only occur at trench segments with v OPD\ 6 0 (epicenter dataset in Fig. 3a with black diamonds and green circles), suggesting that such earthquakes initiate at locked segments of the subduction zone interface that have a rela- tively high normal stress (deviatoric compression) on the subduction zone interface (i.e. a normal stress asperity). Note that the normal stress asperities should be seen separately from asperities that result from variation in friction coeffi- cient along the subduction zone interface (i.e. a frictional asperity). It is evident from the Mohr-Coulomb failure crite- rion that with increasing normal stress an increase in shear stress is required to allow slip along the subduction zone thrust interface (Fig. 5). The deviatoric normal stress on the subduction interface results from the relative motion between the subduction zone hinge and the overriding plate, with convergence between the two inducing deviatoric com- pression and divergence causing deviatoric tension. It fol- lows that the spatial probability of the occurrence of giant subduction thrust earthquakes is therefore linked to the large-scale dynamics of the subducting plate, overriding plate, slab and ambient mantle. This is because slab roll- back/roll-forward processes and subduction-induced mantle flow patterns provide significant control on the relative motions of the subduction zone hinge and overriding plate (Schellart and Moresi, 2013), and also play an important role in determining trench curvature and slab curvature ( Schellart et al., 2007). Another feature of major importance is the presence of buoyant features on the subducting plate, such as plateaus, which affect the local dip angle of the slab, and which can cause local overriding plate shortening and com- pression at the subduction zone interface, thereby forming a potential nucleation zone for epicenters of giant earthquakes. 7. The current work does not provide any insight into the tem- poral probability of giant subduction zone thrust earth- quakes, but it does give insight into their spatial probability. A number of trench segments of active subduc- tion zones have parametric values for v OPD\ , v T\ , v SP\ /v S\ , d ST , C ST and a T that are in the same range as those trench seg- ments that have experienced M W > 8.5 earthquakes (Fig. 9). These include several subduction segments for which histor- ical giant earthquakes (M W > 8.5) have been reported, in par- ticular Cascadia 1700, southern Sumatra 1833, northern Chile 1877 and southern Peru 1868. There are also segments, including Hikurangi-southern Kermadec and Central Amer- ica (Figs. 10 and 11), that have comparable tectonic settings to those segments that have experienced the three largest recorded earthquakes (Chile 1960, Alaska 1964and Sumatra-Andaman 2004, which are characterized by unilateral rupture propagation along the subduction zone interface from a region of compressive normal stress towards a region of neutral stress or deviatoric tension. If the concep- tual model as derived from the largest three earthquakes also applies to these regions, then we predict that they will experience a giant subduction zone thrust earthquake in the ...
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... trench-parallel gradient in overriding plate deformation implies relatively high normal stress (deviatoric compression) on the subduction zone interface in the southwest changing to rela- tively low normal stress (deviatoric tension) towards the northeast (Fig. 10). In analogy with the tectonic settings of the Chile 1960, Alaska 1964 and Sumatra-Andaman 2004 giant earthquakes, one could expect a giant subduction earthquake with an epicenter at the subduction zone plate interface in the southwest Hikurangi re- gion, and unilateral rupture propagation towards the northeast. Fig. 9 shows relatively high scores (S = 4-5) for the two southern- most Hikurangi segments, and the highest scores for the next three segments to the north (S = 6). Wallace et al. (2009) documented high interseismic coupling coefficients (0.8-1.0) in the south but lower ones (0.1-0.2) in the central and northern Hikurangi region, suggesting higher elastic strain buildup in the ...
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... compilations presented in Fig. 3 and Table 2 imply that sev- eral of the subduction zone parameters provide a control on the spatial occurrence of giant subduction zone thrust earthquakes, including v OPD\ , v T\ , d ST , v SP\ /v S\ , C T , C ST and a T . The observed ranges of these parameters for segments with M W > 8.5 are rela- tively narrow (Fig. 3), and the probability that they would result from mere chance is very low (P = 0.001-0.003 for RZD, Table 2). The parameters suggest that those subduction segments with rapid backarc opening (v OPD\ > $3 cm/yr), rapid trench retreat (v T\ > $3 cm/yr), a steep subduction thrust (d ST > $30°), low partitioning (v SP\ /v S\ < 0.3) or high curvature (C T > 1 Â 10 À12 m À2 , C ST > 2 Â 10 À13 m À2 , |a T | > 10°) are incapable of producing M W > 8.5 earth- quakes. In Fig. 9 we present a global map of the active subduction zones, where the 200 km trench segments have been ranked in terms of their predicted capability of generating a giant subduction zone earthquake with M W > 8.5. A high score means a high pre- dicted capability and vice versa. We have ranked the segments in terms of the six subduction zone parameters that appear to provide a control on the spatial occurrence of giant subduction zone thrust earthquakes (v OPD\ , v T\ , d ST , v SP\ /v S\ , C ST and a T ). Note that we have excluded C T because of the high interdependence of C T and C ST (R = 0.94, see Section 2.1). For the lowest possible score (S = 0), the values of the six parameters of a particular trench seg- ment are all outside the range observed for M W > 8.5 earthquakes (using the rupture zone dataset for ranges). For the highest possi- ble score (S = 6), the values are all inside the ...
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... we look at Fig. 9 in more detail, then the map shows that all subduction segments, for which an M W > 8.5 earthquake has been recorded (a total of 32 segments), have the highest score (S = 6), as expected. The map further shows several other subduction zone regions with high scores (S = 5, 6). These regions include most of the South American subduction zone, from the Chile Ridge triple junction to northern Bolivia, (average S = 5.8, range = 4-6), the en- tire Aleutians-Alaska subduction zone (average S = 5.9, range = 5- 6), the entire Sunda subduction zone except for its northernmost segment in northern Andaman (average S = 5.9, range = 5-6), the Japan-Kamchatka segment (average S = 5.2, range = 4-6), the northern Ryukyu-Nankai segment (average S = 5.4, range = 4-6), the entire Cascadia subduction zone (average S = 5.6, range = 5- 6), most of the Central America-Mexico subduction zone (average S = 5.8, range = 4-6), the Makran subduction zone (average S = 5.8, range = 5-6), the Lesser Antilles-Puerto Rico subduction zone (average S = 5.1, range = 4-6) and the southern Kermadec- Hikurangi subduction segment (average S = 5.3, range = 4-6). Sev- eral smaller subduction zones also have high scores, including the North Sulawesi subduction zone (average S = 6), Manila (three middle segments with S = 5) the Calabria subduction zone (average S = 5.5, range = 5-6) and central Hellenic (two segments with S = 5 and ...
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... map predicts that the Scotia subduction zone is the least likely of all subduction zones to produce M W > 8.5 subduction zone thrust earthquakes (average S = 1, observed range = 0-2) due to its rapid backarc opening, rapid trench retreat, steep thrust dip, low partitioning and high curvature (Fig. 9). The map further shows that the New Britain-San Cristobal-New Hebrides subduction zone has low to moderate scores (1-4). In particular, it suggests that the New Hebrides subduction segment is unlikely to produce M W > 8.5 earthquakes (average S = 2.1, observed range = 1-3) due to its rapid backarc opening, rapid trench retreat, steep thrust dip, and low partitioning. The Tonga subduction segment is unlikely to produce M W > 8.5 thrust earthquakes mainly due to its very rapid backarc opening and rapid trench retreat (average S = 3.2, range = 1-4). The Mariana subduction segment, with moderate scores (average S = 4.0, range = 2-6), is also unlikely to produce M W > 8.5 thrust earthquakes, even though it does have one trench segment with a ranking of S = 6 and three with a ranking of S = 5. These high val- ues are for two isolated trench segments and two adjoining seg- ments that are surrounded by segments with lower values, and thus large lateral rupture propagation is unlikely. Finally, the small Halmahera subduction zone has low scores (average S = 1.3, range = 1-2) and is also unlikely to produce M W > 8.5 earthquakes due to its rapid trench retreat, steep slab dip and high ...
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... general, the map in Fig. 9 shows a large number of segments with high scores. From a total of 241 subduction zone segments, 222 have been ranked (19 could not be ranked due to a lack of data), and of these 105 segments have the highest score (S = 6). This indicates that, on a global scale, at least 44% of the active sub- duction zone segments posses six out of six important physical characteristics, predicting they are capable of generating giant sub- duction zone thrust earthquakes with M W > 8.5. Another 42 seg- ments have the second highest score (S = 5). The intermediate scores and low scores all have lower numbers, with n = 35 for S = 4, n = 17 for S = 3, n = 14 for S = 2, n = 8 for S = 1 and n = 1 for S = ...
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... The main source for megathrust earthquakes affecting the Mexican state is the Middle American Trench, with potential fault segments for triggering earthquakes larger than M 8.5 (Schellart and Rawlinson, 2013). The Mexican earthquake catalogue from 1787 (Sawires et al., 2019), shows 56 earthquakes larger or equal to M 7.5; 11 of them larger than M 8, and one earthquake of M 8.6, all of them related to the MAT dynamics (Fig. 1, red dots). ...
Teotihuacan was one of the thriving cultures in the Mesoamerica pre-Hispanic times, located in the Central Valley of Mexico. The city-state was a dominant centre point during the Classic period and its influence affected other contemporaneous cultures. Around the year 550 CE, a continuous decrease in urban population and selective building destruction was noted, accompanied by widespread fire. The layout of the city is identified by an avenue that articulates the political-administrative and religious centres, with such significant and impressive buildings as the Pyramid of the Sun, the Pyramid of the Moon and the Temple of Feathered Serpent. A systematic analysis of building damage in the pyramids reveals several Earthquake Archaeological Effects, (EAEs) potentially related to seismic loading. A damage pattern compatible with a strong ground shaking was also identified in the west staircase of the Old Temple of the Feathered Serpent, in the first rows of the west staircase of the Adosada platform (New Temple), and in the Pyramid of the Sun. In total, five ancient earthquakes have been determined from the damage, dated from the Tzacualli cultural period (1–100 CE), to the Xolalpan – Metepec period (450–550 CE). Unfortunately, this methodology does not determine the earthquake source. Therefore, we consider the possibility that repetitive megathrust earthquakes (Mw > 8.5) from the Middle American Trench (Pacific coast) could be responsible for the spatial pattern of the building damage. This proposal does not conflict with other existing theories for the Teotihuacan abrupt collapse, considering that the sudden overlapping of natural disasters like earthquakes could increase internal warfare (uprising), and civil unrest.
... It is known that main subduction parameters such as convergence rate and age of the PHS plate may strongly influence on the style of subduction, and subsequently the development of arc volcanism 23,28,29 . Slabs younger than 15 Ma dehydrate at shallower depths and are therefore unable to produce sufficient fluids to generate extensive and well-developed volcanic belts, as in Central America 3,30,31 . ...
The subduction of the Philippine Sea (PHS) plate along the Nankai Trough in in southwest Japan is a relatively recent process compared with subduction along the Japan Trench in northeast Japan. However, the tectonic evolution of the PHS plate along the Nankai Trough is still controversial and not fully understood. There are several competing hypotheses based on different estimates for the time variations of convergence rate and plate age. Our study employs numerical modelling of subduction in order to evaluate the slab evolution for the last 15 Myr and aims to evaluate each tectonic scenario against the present-day slab geometry along a profile passing through the Shikoku and Chugoku regions. The modelling strategy involves a parameter study where subduction initiation and various subduction parameters are analyzed in terms of subduction geometry evolution. Two-dimensional visco-elasto-plastic numerical simulations of spontaneous bending subduction predict that convergence rate and plate age variations play an important role in the evolution of subduction geometry. Modeling results after 15 Myr of evolution reveal that the tectonic model based on a high convergence rate between ~ 15 Ma and ~ 3 Ma produces a slab geometry that agrees well with the observed present-day slab shape specific for the Shikoku and Chugoku regions.
... The "plate boundary", i.e. the surface where the two plates are in conctact each others (Abers et al., 2009;Audet et al., 2009), is able to accumulate large amount of stress, depending on many factors (like plate coupling, plunging angle of the subducted plate, physical properties of the material at the subduction interface and the presence of fluids, e.g. Schellart and Rawlinson, 2013), and release it in the so called "megathrust" events (Engdahl and Villaseñor, 2002). Geometrical properties of subduction zones, like curvature and segmentation, can also influence how and how much stress can be cumulated and released along plate boundary (Plescia and Hayes, 2020). ...
We investigate the seismic structure of the mantle wedge of the Apennines subduction zone (Central Mediterranean) using teleseismic receiver function (RF). We inverted RF for both isotropic and anisotropic properties of the mantle wedge, from below the overriding Moho to the “plate boundary”, i.e. the interface that separate the slab from the mantle wedge. Given the distribution of the seismic network, we are able to map out the change in the elastic properties at the transition between southern apennines and the Calabrian arc, given by the change in the subduction style (i.e from the subduction of continental materials to oceanic plate). We found that the anisotropy in the mantle wedge is similar between all seismic stations, generally highly anisotropic ( > 10%), with a direction of the symmetry axis that rotates clockwise from North to South, following the Calabrian arc geometry and likely indicating the mantle flow driven by the slab retreat. The elastic properties of the subducted crust are more heterogeneous. To the North, the subducted crust shows a highly anisotropic ( > 10%) behavior, and it occurs at larger depth (around 70 km depth), where to the South anisotropy is less intense (around 7%) and the subducted crust is shallower (around 60 km depth). These results point out a change in the subduction style that can be given by either a change in the metamorphic phase (more evolved blueschist facies stage to the North, initial greenschist facies stage to the South) or a different origin for the subducted materials (continental to the North and oceanic to the South). The differences in the anisotropic behaviour of the subducted crust are reflected in the topography of the plate boundary, which becomes shallower from North to South, suggesting the existence of either a step in the slab topography or a more gentle ramp.
... Los epicentros para ambos escenarios se han determinado simulando el terremoto más reciente ocurrido, sin embargo, debido al gran tamaño de estos hipotéticos terremotos, en el caso de Nicoya abarcaría casi el total del segmento en cuestión y para el terremoto en la Zona Sur, implicaría la extensión de la ruptura hacia el segmento adyacente en el Pacifico Central (Csi12), como ya se propone en Arroyo-Solórzano y Linkimer (2021). Este potencial y la posible extensión en la ruptura es respaldado por estudios que han llegado a proponer hasta un potencial de 8,5 Mw para un terremoto de subducción en el Sur de Costa Rica (Schellart y Rawlinson, 2013). Los parámetros de ruptura (strilke, dip y rake) para cada segmento se han definido según Hidalgo-Leiva, et al. (2022) (Cuadro 4) y su modelado se ha establecido como "Falla Compleja" de acuerdo con las profundidades del Slab (Hayes et al., 2018). ...
Deterministic seismic risk scenarios are presented for seven potentially hazardous sources for central Costa Rica, estimating maximum accelerations (PGA) and including local effects. Damage and total losses were estimated for each scenario, with four of them being selected due to special interest. An approximation of the number of victims and physical damage was also calculated for the worst-case scenario, during both daytime and nighttime. Critical rupture scenarios would present magnitudes from 6.5 to 8.1 Mw in local faulting and interplate and intraslab subduction sources, with the most harmful scenario being caused by local faulting in the Aguacaliente fault due to its proximity to more densely populated areas. The sector with the greatest economic damage and losses would be to the southeast of San Jose, due to the greater exposure and vulnerability of the buildings, and if the earthquake occurs at night, four to five times more people would be affected.
... First of all, in our simplified model geometry, the shallow dip of our interface is significantly larger than that typically seen in the interface seismogenic zone of most subduction zones (typically 23 ± 8 • ; e.g. Jarrard, 1986;Heuret et al., 2011;Schellart and Rawlinson, 2013). This translates to a typical depth of the downdip limit of the seismogenic zone of 40±5 km (Tichelaar and Ruff, 1993). ...
To a large extent, the thermal structure of a subduction zone determines where seismicity occurs through controls on the transition from brittle to ductile deformation and the depth of dehydration reactions. Thermal models of subduction zones can help understand the distribution of seismicity by accurately modelling the thermal structure of the subduction zone. Here, we assess a common simplification in thermal models of subduction zones, i.e. constant values for the thermal parameters. We use temperature-dependent parameterisations, constrained by lab data, for the thermal conductivity, heat capacity, and density to systematically test their effect on the resulting thermal structure of the slab. To isolate this effect, we use the well-defined, thoroughly studied, and highly simplified model setup of the subduction community benchmark by van Keken et al. (2008) in a 2D finite-element code. To ensure a self-consistent and realistic initial temperature profile for the slab, we implement a 1D plate model for cooling of the oceanic lithosphere with an age of 50 Myr instead of the previously used half-space model. Our results show that using temperature-dependent thermal parameters in thermal models of subduction zones affects the thermal structure of the slab with changes on the order of tens of degrees and hence tens of kilometres. More specifically, using temperature-dependent thermal parameters results in a slightly cooler slab with e.g. the 600 ∘C isotherm reaching almost 30 km deeper. From this, we infer that these models would predict a larger estimated seismogenic zone and a larger depth at which dehydration reactions responsible for intermediate-depth seismicity occur. We therefore recommend that thermo(-mechanical) models of subduction zones take temperature-dependent thermal parameters into account, especially when inferences of seismicity are made.
... Ω overstrength factor. American Plate; ii) the relative geological youth of the oceanic plate; and iii) the physical properties of the faults [1], [2], [3]. Several seismic events of moment magnitude (M w ) larger than 8.0 (epicenters identified with red stars in Fig. 1b) [4]. ...
The satisfactory ‘collapse prevention’ performance level of reinforced concrete (RC) buildings has been widely recognized during recent earthquakes in Chile. However, there is limited research on the actual level of seismic collapse protection. In this study, the seismic collapse behavior of high-rise RC dual wall-frame buildings representative of the Chilean inventory is quantitatively evaluated. A suite of four 16-story structural archetypes was carefully selected and code-based designed assuming two different locations (i.e., high and moderate seismicity zones) and two different soil types (i.e., very stiff and moderately stiff soils). The archetypes were analyzed considering the latest developments in performance-based earthquake engineering implementing incremental dynamic analyses for 3D nonlinear models with sets of Chilean subduction ground motions. Results, expressed in terms of the probability of collapse conditioned on the Maximum Considered Earthquake (MCE) hazard level (<10%) and the collapse probability in 50 years (<1%), showed that all archetypes fully met the targets specified by ASCE 7 for an acceptable ‘life safety’ risk level. These results indeed explain why a very small number of RC building collapses was observed in the recent megathrust earthquakes (Mw>8.0) in Chile. Nevertheless, it was also found that the seismic collapse performance is not uniform, due mainly to the soil type. This observation suggests that the design spectra indicated by the Chilean seismic design code for buildings might need to be revised.
... Seismologists generally assume that large earthquakes are associated with certain subduction settings, with numerous relationships between M max (or the Gutenberg-Richter b-values) and various parameters that characterize the tectonic features of subduction zones (hereafter referred to as "subductionzone parameters") proposed (e.g., Wirth et al. 2022;Marzocchi et al. 2016); for example, the age of the subducting plate (e.g. Ruff and Kanamori 1980;Nishikawa and Ide 2014), angle or curvature radius of the subducting plate (e.g., Ruff and Kanamori 1980;Bletery et , seafloor sediment thickness at the subduction trench (e.g., Ruff 1989;Heuret et al. 2012;Scholl et al. 2015;Brizzi et al. 2018), subducted sediment thickness (Seno 2017), fore-arc structures (e.g., Song and Simons 2003;Wells et al. 2003), upper-plate strain (e.g., Heuret et al. 2012), trench migration velocity (e.g., Schellart and Rawlinson 2013), upper-plate motion (e.g., Scholz and Campos 1995), width of the subducting plate or trench length (Schellart and Rawlinson 2013;Brizzi et al. 2018), and topographic roughness or seafloor smoothness along the subducting plate (e.g., Wang and Bilek 2014;Lallemand et al. 2018) have all been analyzed to infer M max . Schellart and Rawlinson (2013) have investigated 24 physical parameters that characterize subduction zones, but were unable to find any parameters that had a large correlation with M max (correlation coefficient less than 0.5). ...
... Seismologists generally assume that large earthquakes are associated with certain subduction settings, with numerous relationships between M max (or the Gutenberg-Richter b-values) and various parameters that characterize the tectonic features of subduction zones (hereafter referred to as "subductionzone parameters") proposed (e.g., Wirth et al. 2022;Marzocchi et al. 2016); for example, the age of the subducting plate (e.g. Ruff and Kanamori 1980;Nishikawa and Ide 2014), angle or curvature radius of the subducting plate (e.g., Ruff and Kanamori 1980;Bletery et , seafloor sediment thickness at the subduction trench (e.g., Ruff 1989;Heuret et al. 2012;Scholl et al. 2015;Brizzi et al. 2018), subducted sediment thickness (Seno 2017), fore-arc structures (e.g., Song and Simons 2003;Wells et al. 2003), upper-plate strain (e.g., Heuret et al. 2012), trench migration velocity (e.g., Schellart and Rawlinson 2013), upper-plate motion (e.g., Scholz and Campos 1995), width of the subducting plate or trench length (Schellart and Rawlinson 2013;Brizzi et al. 2018), and topographic roughness or seafloor smoothness along the subducting plate (e.g., Wang and Bilek 2014;Lallemand et al. 2018) have all been analyzed to infer M max . Schellart and Rawlinson (2013) have investigated 24 physical parameters that characterize subduction zones, but were unable to find any parameters that had a large correlation with M max (correlation coefficient less than 0.5). ...
... Ruff and Kanamori 1980;Nishikawa and Ide 2014), angle or curvature radius of the subducting plate (e.g., Ruff and Kanamori 1980;Bletery et , seafloor sediment thickness at the subduction trench (e.g., Ruff 1989;Heuret et al. 2012;Scholl et al. 2015;Brizzi et al. 2018), subducted sediment thickness (Seno 2017), fore-arc structures (e.g., Song and Simons 2003;Wells et al. 2003), upper-plate strain (e.g., Heuret et al. 2012), trench migration velocity (e.g., Schellart and Rawlinson 2013), upper-plate motion (e.g., Scholz and Campos 1995), width of the subducting plate or trench length (Schellart and Rawlinson 2013;Brizzi et al. 2018), and topographic roughness or seafloor smoothness along the subducting plate (e.g., Wang and Bilek 2014;Lallemand et al. 2018) have all been analyzed to infer M max . Schellart and Rawlinson (2013) have investigated 24 physical parameters that characterize subduction zones, but were unable to find any parameters that had a large correlation with M max (correlation coefficient less than 0.5). Thus, there is still no consistent relationship between M max and these individual subduction-zone parameters, which suggests that multiple factors may be involved. ...
Large variations in the maximum earthquake magnitude ( $$M_{{\text{max}}}$$ M max ) have been observed among the world’s subduction zones. There is still no universal relationship between $$M_{{\text{max}}}$$ M max and a given subduction-zone parameter, such as plate age, plate dip angle, or plate velocity, which suggests that multiple parameters control $$M_{{\text{max}}}$$ M max . Here, we conduct exhaustive variable selections that are based on three evaluation criteria; leave-one-out cross-validation errors (LOOCVE), Akaike information criterion (AIC), and Bayesian information criterion (BIC) to determine the combination of subduction-zone parameters that best explains $$M_{{\text{max}}}$$ M max . Multiple linear regression analyses are applied using 18 subduction-zone parameters as potential candidates for the explanatory variables of $$M_{{\text{max}}}$$ M max . The minimum BIC is obtained when five variables (trench sediment thickness, existence of an accretionary prism, upper-plate crustal thickness, bending radius of the subducting oceanic plate, and trench depth) are selected as explanatory variables; each variable contributes positively to $$M_{{\text{max}}}$$ M max . Minimum LOOCVE and AIC values are obtained when eight variables (the five parameters for BIC, plus the along-strike plate convergence rate, age of the subducting plate, and maximum depth of the subducting plate) are selected. Our selection of the trench sediment thickness and plate bending radius contributing to $$M_{{\text{max}}}$$ M max is consistent with previous studies. The results show that increasing upper-plate crustal thickness results in a large $$M_{{\text{max}}}$$ M max . In addition to smoothing the subducting-plate interface via subducted sediments, along-dip extension of the crustal area along the convergent plate boundary would be important for generating a large earthquake.
Graphic Abstract
... There is, however, substantial observational evidence that correlations between subducting plate age at the trench and the above parameters are absent or weak, as presented in a variety of global observational studies on active subduction zones. Indeed, it has been shown that a correlation between A and vT^ is absent or even slightly negative , between A and vOPD^ is negligible (Schellart, 2008), between A and d is absent Cruciani et al., 2005), between A and vSP^ is low , and between A and MW_Max is absent (Stein and Okal, 2007;Schellart and Rawlinson, 2013;Bletery et al., 2016). ...
... The data points in the frequency plots represent up to 258, 200-km-wide, trench segments (trench-parallel extent) from a total of 28 active subduction zones (see Table 1). Note that vSP^, vT^, vOP^ and vSP^/vS^ have been determined using the Indo-Atlantic moving hotspot reference frame of O'Neill et al. (2005) and the relative plate motion model of Kreemer et al. (2014), that values of vS^ have been determined using the relative plate motion model of Kreemer et al. (2014), and that values of vOPD^ have been derived and updated from Schellart and Rawlinson (2013). Fig. 4. Diagrams illustrating the relation between various subduction zone parameters and (a,c,e,g,i,k) subducting plate age at the trench (A) or (b,d,f,h,j,l) slab width (W) (trench parallel extent) for up to 258, 200km-wide, trench segments from all active subduction zones on Earth. ...
... Grey dotted lines in (b,d) are non-linear best fit lines (see text). For velocity calculations see figure caption of Fig. 3. Values for d and MW_Max have been derived and updated from Schellart and Rawlinson (2013). at the base of the overriding plate averaged over a 50 km thick mantle layer lying directly below the base of the overriding plate. ...
... Alternatively, the young age of the oceanic plate has been invoked to drive compression in the upper plate, owing to its low negative buoyancy, shallower dip, and increased margin surface (Uyeda & Kanamori, 1979). However, statistical analyses have ruled out the correlation between plate age, convergence velocity, and upper plate deformation (Brizzi et al., 2018;Heuret et al., 2011;Schellart & Rawlinson, 2013). ...
... Other studies correlated upper plate geometry, forearc mantle depth, and gravity anomaly to seismogenic behavior and plate coupling (Bassett and Watts, 2015;Doo et al., 2018;Doo et al., 2020;Grevemeyer & Tiwari, 2006;Song & Simons, 2003). In these studies, the thicker upper plate and backarc compression are inferred to control the occurrence of Great earthquakes along megathrusts (Grevemeyer & Tiwari, 2006;Schellart & Rawlinson, 2013). Studies focused on the seismogenic zone width argue that a serpentinized mantle wedge may limit the downdip extent of this zone off Java to only 30-40 km, compared to >120 km offshore of Sumatra (Simoes et al., 2004). ...
How seismotectonics of convergent margins reconciles with the force balance of subduction is contentious. The comparison of seismotectonics and available slab pull forces along the Sunda convergent margin shows an enigmatic inverse relationship: upper plate thickening and seismicity magnitude are highest along Sumatra and Andaman, where the slab is shorter than ∼300 km; conversely, these are negligible along the Java segment, where the slab reaches deeper, ∼660 km. Using numerical models, we test the role of such slab pull gradients in the force balance of subduction in three‐dimensions, where the slab depth, and therefore its net pull, varies along the trench. We show that in the presence of a “slab step,” the deeper slab drives the convergence of the rigid plate, causing upper plate compression and trench advance in the neighboring trench segments, where a short slab may have no pull to subduct the incoming plate. While neglecting convergence obliquity, the simplified models show relevant along‐trench variations of coupling, trench rotations, and minor strike‐slip shearing due to the slab step, providing a diagnostic strain pattern, with compression/extension atop the short/long slab and minor strike‐slip, increasing in magnitude with depth difference. The modeled tectonic patterns are compared to Sunda margin deformation across scales, from the Cenozoic tectonics to the seismic strain rates, showing remarkable consistency with deformation gradients from Sumatra to Java, potentially illustrating the contribution of the slab step to the seismotectonics of the region.
... Additionally, increased coastal flooding and overtopping due to sea level rise could be one of the main contributors to amplified risk of global port operations (Izaguirre et al. 2020). However, assessment of climate-driven impacts in the port sector is seldom analyzed from a multihazard perspective, which may become relevant in tectonically active coasts, such as those in the Pacific Ring of Fire and Indonesia (Schellart and Rawlinson 2013). The Chilean port system plays a strategic role for integration with the world, as it transfers approximately 90% of the country's international trade. ...
Economic costs due to operational downtime and wave overtopping under the RCP 8.5 scenario are evaluated at 7 Chilean ports. Wave statistics for a historical period (1985–2004), mid-century (2026–2045), and end-of-century projections (2081–2100) are computed with a Pacific-wide model, forced by wind fields from six General Circulation Models. Offshore waves are then downscaled to each port, where a proxy of downtime is computed by comparing wave heights with vessel berthing criteria. The difference in downtime between the historical and future projections is attributed to climate change. Results show that some ports would reduce and others increase downtime for mid-century projections due to local effects. However, by the end-of-century, all ports would experience a reduction in downtime. Additionally, by mid-century, overtopping would increase in northern ports as a combination of extreme waves and sea-level rise (SLR), while in southern ports, it is expected to be slightly reduced. By the end-of century, overtopping would increase in the whole region, mainly driven by SLR. However, overtopping is significantly altered by coseismic uplift/subsidence that may occur during the design-life of coastal works. Finally, a few practical suggestions aimed atimproving infrastructure management and operational conditions at the analyzed ports are outlined.
