The Seismogenic Zone of Subduction Thrust Faults

by Dixon, Timothy H.

• ISBN13: 9780231138666
• ISBN10: 0231138660
• Format: Hardcover
• Copyright: 2007-09-04
• Publisher: Columbia Univ Pr

Summary

Subduction zones, one of the three types of plate boundaries, return Earth's surface to its deep interior. Because subduction zones are gently inclined at shallow depths and depress Earth's temperature gradient, they have the largest seismogenic area of any plate boundary. Consequently, subduction zones generate Earth's largest earthquakes and most destructive tsunamis. As tragically demonstrated by the Sumatra earthquake and tsunami of December 2004, these events often impact densely populated coastal areas and cause large numbers of fatalities.While scientists have a general understanding of the seismogenic zone, many critical details remain obscure. 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 Alaska, and 2004 Sumatra events, rupture along 1000 km or more. Contributors also address why certain subduction zones are fully locked, accumulating elastic strain at essentially the full plate convergence rate, while others appear to be only partially coupled or even freely slipping; whether these locking patterns persist through the seismic cycle; and what is the role of sediments and fluids on the incoming plate.Nineteen papers written by experts in a variety of fields review the most current lab, field, and theoretical research on the origins and mechanics of subduction zone earthquakes and suggest further areas of exploration. They consider the composition of incoming plates, laboratory studies concerning sediment evolution during subduction and fault frictional properties, seismic and geodetic studies, and regional scale deformation. The forces behind subduction zone earthquakes are of increasing environmental and societal importance.

Table of Contents

Preface	p. viii
Introduction	p. 1
The Seismogenic Zone of Subduction Thrust Faults: Introduction	p. 2
The Seismogenic Zone of Subduction Thrust Faults: What We Know and Don't Know	p. 15
The Incoming Plate	p. 41
Sediment Inputs to Subduction Zones: Why Lithostratigraphy and Clay Mineralogy Matter	p. 42
The Thermal State of 18-24 Ma Upper Lithosphere Subducting Below the Nicoya Peninsula, Northern Costa Rica Margin	p. 86
Influence of Subducting Topography on Earthquake Rupture	p. 123
Convergent Margin Structure, Fluids and Subduction Thrust Evolution	p. 147
Pore Pressure and Fluid Flow in the Northern Barbados Accretionary Complex: A Synthesis	p. 148
Pore Pressure within Underthrust Sediment in Subduction Zones	p. 171
Deformation and Mechanical Strength of Sediments at the Nankai Subduction Zone: Implications for Prism Evolution and Decollement Initiation and Propagation	p. 210
The Nicaragua Convergent Margin: Seismic Reflection Imaging of the Source of a Tsunami Earthquake	p. 257
How Accretionary Prisms Elucidate Seismogenesis in Subduction Zones	p. 288
Laboratory Studies	p. 316
Friction of the Smectite Clay Montmorillonite: A Review and Interpretation of Data	p. 317
Fault Friction and the Upper Transition from Seismic to Aseismic Faulting	p. 346
Laboratory-Observed Faulting in Intrinsically and Apparently Weak Materials: Strength, Seismic Coupling, Dilatancy, and Pore-Fluid Pressure	p. 370
Seismic and Geodetic Studies	p. 450
Asperities and Quasi-Static Slips on the Subducting Plate Boundary East of Tohoku, Northeast Japan	p. 451
Anomalous Earthquake Ruptures at Shallow Depths on Subduction Zone Megathrusts	p. 476
Secular, Transient and Seasonal Crustal Movements in Japan from a Dense GPS Array: Implication for Plate Dynamics in Convergent Boundaries	p. 512
Elastic and Viscoelastic Models of Crustal Deformation in Subduction Earthquake Cycles	p. 540
Distinct Updip Limits to Geodetic Locking and Microseismicity at the Northern Costa Rica Seismogenic Zone: Evidence for Two Mechanical Transitions	p. 576
Regional Scale Deformation	p. 600
Collision Versus Subduction: From a Viewpoint of Slab Dehydration	p. 601
Subduction and Mountain Building in the Central Andes	p. 624
List of Contributors	p. 661
Index	p. 665
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