The Role of Translational Landslides in the Evolution of Cuesta Topography

Abstract

AbstractIn recent years, large-scale earthquakes such as the 2004 Mid-Niigata Prefecture Earthquake in Japan and the 1999 Chi-Chi Earthquake in Taiwan have caused rockslides on the back slopes of cuestas. These rockslides in cuestas appear not only in earthquakes but also during rainfalls. This study focuses on the rockslides on cuesta’s back slopes. From field surveys in Japan, Taiwan, Switzerland, and Nepal, we extracted geological, structural, and morphological features common to them. We examined the relationships between these features and triggers, such as pore pressure increases and earthquakes. The majority of landslides initially occur as primary landslides; the forms of these masses then change gradually over a long period. However, our results show that landslides on cuesta’s back slopes slide over and over along the same laminar rock joints and thus hardly change their landscape essence. We demonstrate that rockslides on cuesta’s back slopes play a vital role in the evolution of cuesta landscapes.