Field Test on the Lodging and Uprooting Conditions of Casuarinas and Verification of Those through the 2010 Mentawai Earthquake Tsunami

Abstract

Coastal tree failure conditions such as the lodging, uprooting and breaking are necessary to estimate tsunami energy reduction due to coastal forest. A field test on the lodging and uprooting conditions of Sea casuarinas is carried out on the west coast of Central Sumatra, Indonesia. Based on the field test results, empirical lodging and uprooting conditions of Sea casuarinas are presented. The validity of the conditions is checked through comparison with those data obtained through a field survey of the 2010 Mentawai Earthquake tsunami. It is confirmed that more than 40% of the data satisfy the conditions. Based on the geometric and dynamic characteristics of Sea casuarinas, its scale model in the hydraulic experiments is examined considering the similarity laws for trunk and branches.