Scholarlink

<p>Seismic velocity variations before and after major earthquakes, measured with ambient noise interferometry, reveal time-dependent changes in subsurface properties, but the physical mechanism that causes them remains difficult to identify. Using noise interferometry, we observed a 0.5–1.3% velocity reduction within the upper-crust where the Mw 6.2 Northern Nagano earthquake rupture reached the surface. We combined the inverted 2D image with depth sensitivity to reconstruct the distribution of velocity changes in the shallow crust and show its correlation with the surface rupture and high-slip zones. Our results suggest that the main cause of velocity drop in the first kilometers of depth is damage induced by the mainshock rupture. Both fault-zone damage and near-surface damage from strong ground-shaking are involved, supported by the spatial correlation of velocity perturbations with peak ground acceleration and coseismic slip. These findings highlight fault zone weakening and shaking-induced damage as key drivers of post-earthquake velocity variations.</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

Fault zone damage caused by the mainshock rupture during the 2014 Northern Nagano earthquake

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年11月19日

查看全文
  • Titouan Muzellec,
  • Grazia De Landro,
  • Aldo Zollo

摘要

Seismic velocity variations before and after major earthquakes, measured with ambient noise interferometry, reveal time-dependent changes in subsurface properties, but the physical mechanism that causes them remains difficult to identify. Using noise interferometry, we observed a 0.5–1.3% velocity reduction within the upper-crust where the Mw 6.2 Northern Nagano earthquake rupture reached the surface. We combined the inverted 2D image with depth sensitivity to reconstruct the distribution of velocity changes in the shallow crust and show its correlation with the surface rupture and high-slip zones. Our results suggest that the main cause of velocity drop in the first kilometers of depth is damage induced by the mainshock rupture. Both fault-zone damage and near-surface damage from strong ground-shaking are involved, supported by the spatial correlation of velocity perturbations with peak ground acceleration and coseismic slip. These findings highlight fault zone weakening and shaking-induced damage as key drivers of post-earthquake velocity variations.