Barrier Islands Resilience to Extreme Events: Do Earthquake and Tsunami Play a Role?

Abstract

Barrier islands are indicators of coastal resilience. Previous studies have proven that barrier islands are surprisingly resilient to extreme storm events. At present, little is known about barrier systems’ resilience to seismic events triggering tsunamis, co-seismic subsidence, and liquefaction. The objective of this study is, therefore, to investigate the morphological resilience of the barrier islands in responding to those secondary effects of seismic activity of the Sumatra–Andaman subduction zone and the Great Sumatran Fault system. Spatial analysis in Geographical Information Systems (GIS) was utilized to detect shoreline changes from the multi-source datasets of centennial time scale, including old topographic maps and satellite images from 1898 until 2017. Additionally, the earthquake and tsunami records and established conceptual models of storm effects to barrier systems, are corroborated to support possible forcing factors analysis. Two selected coastal sections possess different geomorphic settings are investigated: (1) Lambadeuk, the coast overlying the Sumatran Fault system, (2) Kuala Gigieng, located in between two segments of the Sumatran Fault System. Seven consecutive pairs of comparable old topographic maps and satellite images reveal remarkable morphological changes in the form of breaching, landward migrating, sinking, and complete disappearing in different periods of observation. While semi-protected embayed Lambadeuk is not resilient to repeated co-seismic land subsidence, the wave-dominated Kuala Gigieng coast is not resilient to the combination of tsunami and liquefaction events. The mega-tsunami triggered by the 2004 earthquake led to irreversible changes in the barrier islands on both coasts.

Fluvial and coastal landform changes in the Aceh River delta (northern Sumatra) during the century leading to the 2004 Indian Ocean tsunami

“…They underwent substantial landward retrogradation and narrowing over the investigated period (Figure 7). This asymmetry is also observed offshore, in the bathymetry of the shoreface (Meilianda et al, 2021), with a steeper shoreface being observed west of the Aceh River, which may result from a more limited input of sediment in the west. Part of the asymmetry may also result from faster subsidence in the western part of the delta, which occupies a tectonic trough located over the trace of the Great Sumatra Fault.…”

“…Other strategies must therefore be adopted to investigate long‐term dynamics on these deltas. Historical maps, aerial photographs, and satellite images have been used to track the evolution of river channels (Gautier et al, 2007; Harmar & Clifford, 2006; Magliulo et al, 2016) and coastal landforms (Jana & Bhattacharya, 2013; Jonah et al, 2016; Kankara et al, 2015; Kumar et al, 2010; Meilianda et al, 2021; Stive et al, 2002) over decades to centuries. Geographic information systems (GISs) are commonly used to overlap digitized historical maps, aerial photographs, and satellite images (Bisson & Bini, 2012; Giacomelli et al, 2018) and create time‐series of landscape change.…”

Landscapes and Landforms of Terrestrial and Marine Areas: A Way Forward

“…The papers concerning the analysis of terrestrial and marine landforms in coastal and shallow water specifically deal with geomorphological mapping and landscape evolution [22,23], geoheritage and geodiversity [18,19], geohazards [16,20,21], and marine and landscape ecology [28].…”

“…Meilianda et al [16] performed a spatial analysis on multisource datasets to investigate barrier islands' morphological changes along Sumatra Island coasts (Indonesia), as a result of the secondary effects of the seismic activity related to the Sumatra-Andaman subduction and the Great Sumatran Fault system. In particular, the authors documented that the 2004 megatsunami irreversibly changed barrier islands on the investigated stretches of the coast.…”

“…Most of the papers included in this volume deal with landscapes and landforms of the Mediterranean region. However, a case study from coastal areas of the Indian Ocean is also included [16]. Special Issue contributions took into consideration both the present sea level, its past oscillations, and possible future variations in terms of sea-level rise.…”