Subducted seafloor relief stops rupture in South American great earthquakes: Implications for rupture behaviour in the 2010 Maule, Chile earthquake

Sparkes, R.; Tilmann, Frederik; Hovius, Niels; Hillier, John K.

doi:10.1016/j.epsl.2010.07.029

Cited by 70 publications

(65 citation statements)

References 30 publications

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“…The spatial location of the aftershock clusters may be controlled by fracture networks induced by the subducting seamounts (Wang & Bilek 2011), which may well represent the cause for the increased seismicity in the area of the JFR in the interseismic period. Parallel to creating heterogeneous stresses, large subducted relief (>1000 m) creates unfavourable conditions for ruptures to propagate across (Sparkes et al 2010). Therefore, the subduction of the JFR is suggested to control the southern boundary of the 2015 Illapel earthquake and the clustering of aftershocks between 32 • S and 33 • S.…”

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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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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“…For example, Kodaira et al (2000) imaged a subducted seamount at depth in the Nankai subduction zone that they suggest acted as a barrier in the 1946 M w 8.3 Nankai earthquake rupture. Other examples of significant subducted topography acting as rupture barriers include along the South American margin (e.g., Perfettini et al, 2010;Sparkes et al, 2010;Geersen et al, 2015), Sumatra margin (e.g., Chlieh et al, 2008;Henstock et al, 2016), and Japan Trench (e.g., Simons et al, 2011;Duan, 2012). In some cases, the subducting topography may initially act as a barrier and then fail later in the rupture, producing significant slip, as proposed for the 2001 M w 8.4 Peru earthquake (Robinson et al, 2006).…”

Section: Role Of Rough Downgoing Plate Topographymentioning

confidence: 99%

“…The way in which the rough plate affects earthquake rupture appears to be more variable. From large seamounts entering the Japan Trench (e.g., Nishizawa et al, 2009), to smaller seamounts leaving scars in the forearc in Costa Rica (e.g., Ranero and von Huene, 2000), and large seamounts and ridges entering the subduction zone along Peru, Chile, and elsewhere (e.g., Spence et al, 1999;Robinson et al, 2006;Sparkes et al, 2010;Marcaillou et al, 2016), these features are significant enough to likely affect megathrust earthquakes, although exactly how is an active debate. Kelleher and McCann (1976) correlated locations of great earthquakes with the relatively smooth bathymetry portions of subduction zones, finding only moderate-magnitude earthquakes occurring in areas with significant subducting bathymetry such as aseismic ridges.…”

Section: Role Of Rough Downgoing Plate Topographymentioning

confidence: 99%

Subduction zone megathrust earthquakes

2018

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Subduction zone megathrust faults host Earth's largest earthquakes, along with multitudes of smaller events that contribute to plate convergence. An understanding of the faulting behavior of megathrusts is central to seismic and tsunami hazard assessment around subduction zone margins. Cumulative sliding displacement across each megathrust, which extends from the trench to the downdip transition to interplate ductile deformation, is accommodated by a combination of rapid stick-slip earthquakes, episodic slow-slip events, and quasi-static creep. Megathrust faults have heterogeneous frictional properties that contribute to earthquake diversity, which is considered here in terms of regional variations in maximum recorded magnitudes, Gutenberg-Richter b values, earthquake productivity, and cumulative seismic moment depth distributions for the major subduction zones. Great earthquakes on megathrusts occur in irregular cycles of interseismic strain accumulation, foreshock activity, main-shock rupture, postseismic slip, viscoelastic relaxation, and fault healing, with all stages now being captured by geophysical monitoring. Observations of depth-dependent radiation characteristics, large earthquake slip distributions, variations in rupture velocities, radiated energy and stress drop, and relationships to aftershock distributions and afterslip are discussed. Seismic sequences for very large events have some degree of regularity within subduction zone segments, but this can be complicated by supercycles of intermittent huge ruptures that traverse segment boundaries. Factors influencing variability of large megathrust ruptures, such as large-scale plate structure and kinematics, presence of sediments and fluids, lower-plate bathymetric roughness, and upper-plate structure, are discussed. The diversity of megathrust failure processes presents a suite of natural hazards, including earthquake shaking, submarine slumping, and tsunami generation. Improved monitoring of the offshore environment is needed to better quantify and mitigate the threats posed by megathrust earthquakes globally.

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“…3). The 3 km elevation difference is above the threshold identified by Sparkes et al (2010) as the minimum to affect earthquake segmentation. Global positioning system data from the islands (Hsu et al, 2006) show that southward propagation of the A.D. 2005 rupture ceased at the subducted basement high (Fig.…”

Section: Origin and Effects Of Basement Topographymentioning

confidence: 99%

“…Links between topography on the downgoing plate and this segmentation are debated (Wang and Bilek, 2011;Kopp, 2013). Topography exceeding 1 km correlates with segment boundaries west of South America (Sparkes et al, 2010), but the mechanism, whether by changing mechanical coupling or fault zone physical properties, remains controversial. Some studies argue that subducting topography exceeding the height of the décolle-ment zone strengthens the plate boundary, increasing coupling and acting as a seismic asperity (Cloos, 1992;Scholz and Small, 1997;Bilek et al, 2003); others argue that subducting topography fractures and increases fluid content in the overriding plate, decreasing coupling and limiting strain accumulation to suppress seismogenic rupture (Kelleher and McCann, 1976;Wang and Bilek, 2011;Singh et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Downgoing plate topography stopped rupture in the A.D. 2005 Sumatra earthquake

Henstock

McNeill

Bull

et al. 2015

Geology

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Earthquakes in subduction zones rupture the plate boundary fault in discrete segments. One factor that may control this segmentation is topography on the downgoing plate, although it is controversial whether this is by weakening or strengthening of the fault. We use multichannel seismic and gravity data to map the top of the downgoing oceanic crust offshore central Sumatra, Indonesia. Our survey spans a complex segment boundary zone between the southern termination of the M w = 8.7, A.D. 2005 Simeulue-Nias earthquake, and the northern termination of a major 1797 earthquake that was partly filled by an M w = 7.7 event in 1935. We identify an isolated 3 km basement high at the northern edge of this zone, close to the 2005 slip termination. The high probably originated at the Wharton fossil ridge, and is almost aseismic in both local and global data sets, suggesting that while the region around it may be weakened by fracturing and fluids, the basement high locally strengthens the plate boundary, stopping rupture propagation.

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Subducted seafloor relief stops rupture in South American great earthquakes: Implications for rupture behaviour in the 2010 Maule, Chile earthquake

Abstract: 7Great subduction earthquakes cause destructive surface deformation and ground 8

Cited by 70 publications

References 30 publications

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

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

Subduction zone megathrust earthquakes

Downgoing plate topography stopped rupture in the A.D. 2005 Sumatra earthquake

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