Measuring short-term coastline changes from an active volcano (Ambae, Vanuatu) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Earth Science at Massey University, Palmerston North, New Zealand
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Date
2021
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Massey University
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Ambae is a small island in Vanuatu which in recent times has seen high levels of volcanic activity. Between August 2017 and December 2018, several volcanic eruptions occurred, some larger than others, but all with varying effects. A major eruption occurred in July 2018, causing sediment build-up at different locations along the western coastline of the island. The sediment build-up appeared to increase over months, and receded over continuing months. Analyses were completed to assess and evaluate satellite platforms and their ability to aid in gaining an understanding of coastal change over the time period between August 2017 and December 2018. Imagery from each platform was combined with the use of various water indices which aided in measuring the magnitude of coastal change over the time period. Sentinel-2, Landsat 8 and Planet satellite platforms were analysed for their effectiveness when used in conjunction with water indices, including the Normalised Difference Water Index (NDWI), Modified Normalised Difference Water Index (MNDWI), and Automated Water Index (AWEI). The Sentinel-2 platform with the NDWI water index was found to be the most effective for analysing the coastal change. The combination of this satellite platform with this index enabled a quantitative measurement of land change over a specific period of time (August 2017 to December 2018).