Scholarlink

Abstract <p>The present study examines how variations in the dip angle of the subduction interface influence the distribution of coseismic slip during great megathrust earthquakes (Mw ≥ 8.8). I analysed the five largest instrumentally recorded events: The 1960 Valdivia (Mw 9.5), 1964 Alaska (Mw 9.2), 2004 Sumatra (Mw 9.1), 2011 Tohoku (Mw 9.1), and 2010 Maule (Mw 8.8) earthquakes. The published finite fault models for these events are compared with the three-dimensional geometry of their subduction zones as defined by the Slab 1.0 model. The analysis shows that coseismic slip is mainly concentrated in areas with low dip angles (below 25°–30°), and that rupture propagation along strike is limited by segments exhibiting changes in slab geometry, such as steeper or flatter dips. These geometric variations act as barriers that segment the megathrust and affect the potential maximum rupture area. An exception is the 2004 Sumatra earthquake, where a significant change in dip appears to have promoted, rather than impeded, rupture propagation. This study concludes that the geometry of the subduction interface, especially its dip angle, plays a fundamental role in controlling the size and segmentation of great megathrust earthquakes.</p> Research highlights <p><UnorderedList Mark="Bullet"> <ItemContent> <p>Megathrust earthquakes with Mw ≥ 8.8 show systematic concentration of coseismic slip in shallow-dip segments (&lt;25°) of subduction interfaces.</p> </ItemContent> <ItemContent> <p>Variations in slab dip geometry act as structural barriers that control rupture segmentation and limit along-strike propagation.</p> </ItemContent> <ItemContent> <p>Comparative analysis of five great earthquakes reveals that subduction interface geometry is a first-order control on rupture size and slip distribution.</p> </ItemContent> </UnorderedList></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Geometric controls on slip distribution and segmentation of the largest megathrust earthquakes

  • 期刊论文

  • 发表日期：

    2026年7月8日

查看全文
  • Mahesh N Shrivastava

摘要

Abstract

The present study examines how variations in the dip angle of the subduction interface influence the distribution of coseismic slip during great megathrust earthquakes (Mw ≥ 8.8). I analysed the five largest instrumentally recorded events: The 1960 Valdivia (Mw 9.5), 1964 Alaska (Mw 9.2), 2004 Sumatra (Mw 9.1), 2011 Tohoku (Mw 9.1), and 2010 Maule (Mw 8.8) earthquakes. The published finite fault models for these events are compared with the three-dimensional geometry of their subduction zones as defined by the Slab 1.0 model. The analysis shows that coseismic slip is mainly concentrated in areas with low dip angles (below 25°–30°), and that rupture propagation along strike is limited by segments exhibiting changes in slab geometry, such as steeper or flatter dips. These geometric variations act as barriers that segment the megathrust and affect the potential maximum rupture area. An exception is the 2004 Sumatra earthquake, where a significant change in dip appears to have promoted, rather than impeded, rupture propagation. This study concludes that the geometry of the subduction interface, especially its dip angle, plays a fundamental role in controlling the size and segmentation of great megathrust earthquakes.

Research highlights

Megathrust earthquakes with Mw ≥ 8.8 show systematic concentration of coseismic slip in shallow-dip segments (<25°) of subduction interfaces.

Variations in slab dip geometry act as structural barriers that control rupture segmentation and limit along-strike propagation.

Comparative analysis of five great earthquakes reveals that subduction interface geometry is a first-order control on rupture size and slip distribution.