Local wisdoms such as a tradition, land-use system and etc. had sometimes mitigated tsunami damages in Indonesia. The effective use of those local wisdoms is strongly desired especially in developing countries, because it is quite difficult for those countries to allocate enough budgets for constructing hard type countermeasures against tsunami. Among local wisdoms against tsunami hazard, this study evaluates the efficiency of a hollow topography which can be seen on the beach along Lampon village in Indonesia Artificial hollows are arrayed on the beach as one of the local wisdoms in Lampon village to reduce the intensity of inundated tsunami flow. The numerical simulation of tsunami inundation is conducted to evaluate the efficiency of this hollow topography. Furthermore, this study evaluates the efficiency of some contrivances, such a combination of vegetation area and a multiple-use of hollow and embankment topography, in order to enhance the performance of countermeasure based on the local wisdom.
The flow velocity of tsunami wave was estimated by using Particle Image Velocimetry(PIV) and Particle Tracking Velocimetry(PTV). These methods have many advantages that can be used to measure velocity under limited data such as the 2011 off the Pacific Coast of Tohoku Tsunami. The results of video image analysis are evaluated by comparing with theoritical approach. The collected video image is stabilized and rectified in the pre-processing to enhance the accuracy of PIV method, whereas the proposed theoretical method is based on conservation equation. It is found that the estimated flow velocity range is consistent regardless of the method. The method is expected to perform well for analyzing videos and providing information in tsunami cases where there is no adequate measurement data.