Remote sensing and field assessment of tsunami effects on coastal pond aquaculture in northern Sumatra

An attempt was made to conduct spatial assessment of the pattern and extent of damage to coastal aquaculture ponds along the east coast of Aceh province in Sumatra, Indonesia, resulting from the tsunami event of 26 December 2004. High-resolution satellite imagery, i.e., SPOT-5 multispectral scenes covering the 700 km stretch of the coast, acquired before and after the tsunami, were digitally enhanced and visually interpreted to delineate pockets of aquaculture ponds that were discerned to be damaged and relatively intact. Field checks were conducted at 87 sites in the four eastern coastal districts. The results indicate that SPOT-5 multispectral imagery was minimally sufficient to detect areas of damaged and relatively intact aquaculture ponds, but the 10-m spatial resolution poses limitations to evaluating the extent of pond damage. Nevertheless, the 60 km swath of the imagery makes it reasonably affordable for large-area assessment to identify pockets of severe damage for targeting more detailed assessments. The image maps produced from a mosaic of the SPOT-5 scenes can also serve as base maps for spatial planning in the challenging task of reconstruction and rehabilitation of the disrupted livelihoods of the coastal communities.Remote sensing, Disasters, Spatial analysis, Coastal zone, ISEW, Indonesia, Aceh,

Remote Sensing and Field Assessment of Tsunami Effects on Coastal Pond Aquaculture in Northern Sumatra

An attempt was made to conduct spatial assessment of the pattern and extent of damage to coastal aquaculture ponds along the east coast of Aceh province in Sumatra, Indonesia, resulting from the tsunami event of 26 December 2004. High-resolution satellite imagery, i.e., SPOT-5 multispectral scenes covering the 700 km stretch of the coast, acquired before and after the tsunami, were digitally enhanced and visually interpreted to delineate pockets of aquaculture ponds that were discerned to be damaged and relatively intact. Field checks were conducted at 87 sites in the four eastern coastal districts. The results indicate that SPOT-5 multispectral imagery was minimally sufficient to detect areas of damaged and relatively intact aquaculture ponds, but the 10-m spatial resolution poses limitations to evaluating the extent of pond damage. Nevertheless, the 60 km swath of the imagery makes it reasonably affordable for large-area assessment to identify pockets of severe damage for targeting more detailed assessments. The image maps produced from a mosaic of the SPOT-5 scenes can also serve as base maps for spatial planning in the challenging task of reconstruction and rehabilitation of the disrupted livelihoods of the coastal communities

Assessment of post-tsunami disaster land use/land cover change and potential impact of future sea-level rise to low-lying coastal areas: A case study of Banda Aceh coast of Indonesia

© 2019 The objective of this study is to investigate the impact of the projected sea-level rise to the coastal land use/land cover (LULC) at a disaster-prone coastal area, encompassing an engineering time-scale, based on a couple of sea-level rise scenarios. We investigate the Banda Aceh coast, a low-lying coastal area vulnerable to multiple hazards such as tsunamis and co-seismic land subsidence, which is typical along the Indonesian coastlines. Three sets of multi-temporal Google Earth Engine images acquired in 2004 (pre-tsunami December 2004), 2011 and 2017 were utilized to obtain the areal coverage of various types of LULC. The scenarios of coastal inundation were pre-determined at elevation +1.0 m and +1.5 m projecting the sea-level rise in the next couple centuries. Aquaculture ponds, buildings and bare land are the top three most pre-dominant land covers in Banda Aceh coast. The finding of this study reveals that the aquaculture ponds are at the highest risk to the future sea-level rise, and potentially contribute to the unproductive seawater inundated area. The bare land which has a huge potential to be converted into settlement area (buildings, housing, etc.), experienced remarkable loss due to both future inundation scenarios. The coastal area of Banda Aceh in the next couple of centuries, thus, will be highly vulnerable to the projected sea-level rise, providing the fast-growing and ever-expanding built environment very close to the coastline. A sustainable coastal management taking into account the disaster risk should, therefore, be incorporated within the decision making for the protection of the coastal area

A Hydrodynamics Perspective for the 2004 Megatsunami

The megatsunami of 26 December 2004 was the first tsunami with transoceanic impact since the 1960 Great Chilean and 1964 Great Alaskan tsunamis. Because of the distribution of deaths among a large portion of the nations of the world, the 2004 Boxing Day tsunami is the first universal natural disaster of modern times. For the purpose of adequate mitigation of future tsunamis, it is important to understand which factors control most critically the final characteristics of the flooding, namely runup and inundation. Their successful modeling requires not only a credible database of inundation parameters, against which models can be tested through numerical simulation of the generation, propagation to the local shores, and final interaction of the tsunami with the target beaches, but also in situ observations that help identify unusual impact and previously unrecognized or controversial flow patterns. Here, I comment on the hydrodynamic lessons -mostly relearned- and describe remaining challenges

Operational tsunami modelling with TsunAWI – recent developments and applications

In this article, the tsunami model TsunAWI (Alfred Wegener Institute) and its application for hindcasts, inundation studies, and the operation of the tsunami scenario repository for the Indonesian tsunami early warning system are presented. TsunAWI was developed in the framework of the German-Indonesian Tsunami Early Warning System (GITEWS) and simulates all stages of a tsunami from the origin and the propagation in the ocean to the arrival at the coast and the inundation on land. It solves the non-linear shallow water equations on an unstructured finite element grid that allows to change the resolution seamlessly between a coarse grid in the deep ocean and a fine representation of coastal structures. During the GITEWS project and the following maintenance phase, TsunAWI and a framework of pre- and postprocessing routines was developed step by step to provide fast computation of enhanced model physics and to deliver high quality results