The seismogenic zone of subduction thrust faults pdf

The fault is aseismic in the seaward updip portion and landward downdip of a critical point. Large thrust earthquakes along subduction zones pose a seismic and tsunami threat to densely populated coastal cities. We perform fully coupled earthquake and tsunami simulations for three subduction zones. Earthquakes with slow rupture velocities are the most efficient tsunami generators, and this earthquake was classified as a tsunami earthquake tsunami. Characterizing the seismogenic zone of a major plate boundary subduction thrust. This volume attempts to answer such fundamental concerns as why some interplate subduction earthquakes are relatively modest in rupture length greater than 100 km while others, such as the great m greater than 9 1960 chile, 1964. The seismogenic zone of subduction thrust faults hyndman 1997. The shallow inclination provides a large surface area, or seismogenic zone, subject to brittle failure and the production of earthquakes figure 1. Such crustal splay faults are outofsequence thrusttype faults that break through the upper plate and contribute to significant deformation and thicken.

The seismogenic zone of subduction thrust faults columbia. Figure 1b shows schematic representations of the surface of the seismogenic zone of subduction thrust faults. Two reports in this issue, based on seismological observations, emphasize the key role of the structural evolution of faults. Abstract interplate thrust faults in subduction zones host the largest earthquakes and majority of seismic energy release on earth. Download it once and read it on your kindle device, pc, phones or tablets. Subduction zones, one of the three types of plate boundaries, return earths surface to its deep interior. Splay fault branching along the nankai subduction zone. Because subduction zones are gently inclined at sh. The seismogenic zone extends up to 55 km farther landward than previously estimated hyndman and wang, 1993 dashed line, including under the coastline of. The fault is aseis mic in the seaward updip portion and landward downdip of a critical point. Thermal constraints on the seismogenic portion of the.

Although plate tectonics provides the underlying kinematic explanation for subductionzone earthquakes, only a narrow portion of the platecontact zone actually generates them. Within the narrowly defined seismic zone, most of the convergence may occur in earthquakes. Seismogenic zone deep drilling and measurement report of detailed planning group joides, ocean drilling program, august 6, 1999 r. Depthvarying rupture properties of subduction zone. Generalized diagram of a subduction zone, with an expandedscale view of the seismogeniczone interface. Consequently, subduction zones generate earths largest earthquakes and most destructive tsunamis. We have developed numerical models of the thermal structure of the mexico subduction zone to examine the factors that affect the temperature of the subduction thrust fault. Hikurangi margin, new zealand article pdf available in geochemistry geophysics geosystems 1010 october 2009. Multiple damage zone structure of an exhumed seismogenic.

The seismogenic zone is bounded by the upper and szibductio. What controls the location and size of seismic rupture along the 43,500 km of the worlds subduction faults. Because subduction zones are gently inclined at shallow depths and depress earths temperature gradient, they have the largest seismogenic. Goals of the seismogenic zone experiment seize are show in this. Origin of a crustal splay fault and its relation to the. Casey moore 12 earth and planetary sciences department. The thickness of subduction plate boundary faults from the.

The thermal control implies that subduction thrust faults with shallow dip have wider seismogenic zones compared to those with steep dip. The insights from recovered core across active faults can be used to help calibrate the seismic reflection images from farther landward and deeper on the faults. Laboratoryobserved faulting in intrinsically and apparently weak materials. Characterizing the seismogenic zone of a major plate. The cascadia primary seismogenic structure model, as proposed here, has important implications for great earthquake shaking and related damage to major metropolitan centers in vancouver, canada, and seattle, olympia, portland, salem, and eugene, usa, in the event of a future major megathrust rupture in the central cascadia subduction zone. Map of cascadia subduction zone with probable megathrust seismogenic zone, portion of plate boundary fault from 150 350. Multiple damage zone structure of an exhumed seismogenic megasplay fault in a subduction zone a study from the nobeoka thrust drilling project. Subduction thrusts exhumed from seismogenic depths may record the dynamic slip processes during subduction zone earthquakes.

Depthvarying rupture properties of subduction zone megathrust faults. The seismogenic zone of subduction thrust faults ebook by. In this paper, we shift the focus from individual faults to seismogenic structures which. Subduction zone thrust faults produce the largest earthquakes on the earth because the plateboundary thrust is in a zone of high strain rate and is inclined shallowly. Because subduction zones are gently inclined at shallow depths and depress earths temperature gradient, they have the largest seismogenic area of any plate boundary. Use features like bookmarks, note taking and highlighting while reading the seismogenic zone of subduction thrust faults margins theoretical and experimental. Deformation and hydrofracture in a subduction thrust at. Distribution of deformation in the seismogenic zone as depicted in figure 2 the seismogenic zone comprises a rock volume, not just a twodimensional interface along the.

Composition and state variations on the subduction thrust. Why lithostratigraphy and clay mineralogy matter, by michael b. These earthquakes can be generated repeatedly on a certain portion of the plateboundary interface, which is called the seismogenic zone. Real subduction zones display remarkable diversity in fault geometry and structure, and accordingly exhibit a variety of styles of earthquake rupture and tsunamigenic behavior. The seismogenic zone of subduction thrust faults, ed. The thickness of an active plate boundary fault is an important parameter for understanding the strength and spatial heterogeneity of fault behavior.

The seaward updip limit of the seismogenic zone helps to determine the size of the tsunami, whereas the landward downdip limit. Subduction zones can generally be traced at the surface of the earth because they are associated with. The tsunami reached java and bali, with runups up to 14 m 46 ft on the east java coast and up to 5 m. The thickness of subduction plate boundary faults from the sea. Subduction zones, one of the three types of plate boundaries,return earths surface to its deep interior. The seismogenic zone of subduction thrust faults hyndman. One wellstudied exhumed major fault zone in a subduction setting is the nobeoka thrust in the kyushu shimanto belt, southwest japan, which is a fossilized subduction zone megasplay fault e. Introduction great earthquakes occur in the seismogenic portion of subduction zone megathrusts scholz and campos, 2012. Gsa data repository 2027 supplementary material the. This earthquake occurred with a moment magnitude of 7.

Many of these research papers have pdf downloads available on the site. How accretionary prisms elucidate seismogenesis in. The seismogenic zone of subduction thrust faults, island. Silica precipitation potentially controls earthquake. Because subductionzones are gently inclined at sha. Rigidity variations with depth along interplate megathrust. Fluidization of granular material in a subduction thrust. The seismogenic zone of subduction thrust faults on jstor.

The seismogenic zone of subduction thrust faults margins. Seismogenesis in subduction zones mcgill university. An earthquake machine for simulating subduction zone. Pdf the seismogenic zone of subduction thrust faults. Distribution of deformation in the seismogenic zone as depicted in figure 10. Wallace, martin reyners, ursula cochran, and stephen bannister gns science, p. Introduction in earthquakerelated neotectonics, faults are usually the focus of earthquake predictionforecast studies. Pdf characterizing the seismogenic zone of a major plate. We have compiled direct measurements of the thickness of subduction thrust faults from active and ancient examples observed by ocean drilling and field studies in accretionary wedges. Downdip variations in seismic reflection character. For many subduction zones the downdip seismogenic width defined by these limits is much less than previously assumed. Subduction zone, crustal structure, seismicity, strain, deformation 1. In order for an exhumed subduction thrust to preserve its emplacement history in the seismogenic zone, deformation must be isolated from previous and subsequent events.

Abstract subduction thrust faults generate earthquakes over a limited depth range. Deformation and hydrofracture in a subduction thrust at seismogenic. Seismogenic processes on the subduction thrust part 1. Fully coupled simulations of megathrust earthquakes and. Aaron wech supervised by tim stern, victoria university of wellington eqc funded project 10u609. Read the seismogenic zone of subduction thrust faults by available from rakuten kobo. They are aseismic in their seaward updip portions and. The seismogenic zone of subduction thrust faults margins theoretical and experimental earth science series kindle edition by dixon, timothy, moore, j. Seismogenic processes on the subduction thrust part 1hikurangi subduction zone, and part 2 alpine fault. The seismogenic zone of subduction thrust faults edited. The subducting plate age and thus heat flow, and the thickness of the insulating sediments on the incoming plate, are also very important to the thermal regime and thus to the seismogenic width. Numerical thermal models have been employed to estimate temperatures on the subduction thrust planes of four continental subduction zones.