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.

Preface
Part I. Introduction
1. The Seismogenic Zone of Subduction Thrust Faults: Introduction, by Timothy H. Dixon and J. Casey Moore
2. The Seismogenic Zone of Subduction Thrust Faults: What We Know and Don't Know, R. D. Hyndman
Part II. The Incoming Plate
3. Sediment Inputs to Subduction Zones: Why Lithostratigraphy and Clay Mineralogy Matter, by Michael B. Underwood
4. The Thermal State of 18 –24 Ma Upper Lithosphere Subducting Below the Nicoya Peninsula, Northern Costa Rica Margin, by M. Hutnak, A. T. Fisher, C. A. Stein, R. Harris, K. Wang, E. Silver, G. Spinelli, M. Pfender, H. Villinger, R. MacKnight, P. Costa Pisani, H. DeShon, and C. Diamente
5. Influence of Subducting Topography on Earthquake Rupture, by Susan L. Bilek
Part III. Convergent Margin Structure, Fluids and Subduction Thrust Evolution
6. Pore Pressure and Fluid Flow in the Northern Barbados Accretionary Complex: A Synthesis, by Barbara A. Bekins and Elizabeth J. Screaton
7. Pore Pressure within Underthrust Sediment in Subduction Zones, by Demian M. Saffer
8. Deformation and Mechanical Strength of Sediments at the Nankai Subduction Zone: Implications for Prism Evolution and Decollement Initiation and Propagation, by Julia K. Morgan, Elizabeth B. Sunderland, né E. Blanche Ramsey, and Maria V. S. Ask
9. The Nicaragua Convergent Margin: Seismic Reflection Imaging of the Source of a Tsunami Earthquake, by Kirk D. McIntosh, Eli A. Silver, Imtiaz Ahmed, Arnim Berhorst, Cesar R. Ranero, Robyn K. Kelly, and Ernst R. Flueh
10. How Accretionary Prisms Elucidate Seismogenesis in Subduction Zones, by J. Casey Moore, Christie Rowe, and Francesca Meneghini
Part IV. Laboratory Studies
11. Friction of the Smectite Clay Montmorillonite: A Review and Interpretation of Data, by Diane E. Moore and David A. Lockner
12. Fault Friction and the Upper Transition from Seismic to Aseismic Faulting, by Chris Marone and Demian M. Saffer
13. Laboratory-Observed Faulting in Intrinsically and Apparently Weak Materials: Strength, Seismic Coupling, Dilatancy, and Pore-Fluid Pressure, by N. M. Beeler
Part V. Seismic and Geodetic Studies
14. Asperities and Quasi-Static Slips on the Subducting Plate Boundary East of Tohoku, Northeast Japan, by Akira Hasegawa, Naoki Uchida, Toshihiro Igarashi, Toru Matsuzawa, Tomomi Okada, Satoshi Miura, and Yoko Suwa
15. Anomalous Earthquake Ruptures at Shallow Depths on Subduction Zone Megathrusts, by Thorne Lay and Susan Bilek
16. Secular, Transient and Seasonal Crustal Movements in Japan from a Dense GPS Array: Implication for Plate Dynamics in Convergent Boundaries, by Kosuke Heki
17. Elastic and Viscoelastic Models of Crustal Deformation in Subduction Earthquake Cycles, by Kelin Wang
18. Distinct Updip Limits to Geodetic Locking and Microseismicity at the Northern Costa Rica Seismogenic Zone: Evidence for Two Mechanical Transitions, by Susan Y. Schwartz and Heather R. DeShon
Part VI. Regional Scale Deformation
19. Collision Versus Subduction: From a Viewpoint of Slab Dehydration, by Tetsuzo Seno
20. Subduction and Mountain Building in the Central Andes, by Jonas Kley and Tim Vietor
List of Contributors
Index