Abstract

Indonesia is periodically affected by severe volcanic eruptions and earthquakes, which are geologically coupledto the convergence of the Australian tectonic plate beneath the Sunda Plate. This work is aimed at performing ananalysis of ground displacements over Indonesian sites through Multi-temporal SAR interferometry (MTI). Twotest sites, in Sumatra and Java, have been selected according to the following requirements: presence of groundinstabilities, possibly related to onshore active faults or volcanoes; good expected interferometric coherence,availability of reliable archived interferometric SAR datasets, availability of ancillary geophysical data.Displacement maps have been obtained by processing COSMO-SkyMed and Sentinel-1 datasets available on thearea, through SPINUA algorithm, which performs Persistent Scattering (PS) analysis. The use of datasets comingfrom two datasets, allows cross-validating final results. The processing of Sentinel-1 data has been more complexw.r.t. that of COSMO-SkyMed data, as standard MTI displacement maps showed strong artifacts, likely due toresidual atmospheric contributions and orbital errors. In order to overcome this problem, an alternative processingscheme has been experimented.The tectonic analysis in Indonesia is difficult because the vegetation cover in the area causes lack of PS along andacross the faults. Our MTI results provided useful information about the ground stability/instability within theselected test sites. In particular, concerning the tectonic activity in Sumatra, the MTI displacement analysis seemsto confirm the inactivity of the Aceh fault segment, as foreseen by geodetic studies. Also, in the Java test site nodisplacement signal was detected related to possible activity of the faults present in the area.Besides the tectonic activity, ground displacements were also identified basically reflecting local effects. Thecauses of these displacements were investigated by using ancillary geological data, and in situ inspections.The subsidence phenomena are mainly related to the presence of unconsolidated coastal/alluvial sediments andgroundwater pumping.An interesting example concerns a coastal area in Banda Aceh, which was overrun and completely destroyedby the 2004 tsunami. Most subsiding PS targets are positioned on port facilities structures and embankments.Extensive rebuilding and new constructions in the area add weight to the unconsolidated sediments. There is alsoan extensive presence of seasonally flooded crops and salt production flats. This suggests that the subsidenceoccurring in the area is probably related to compaction of sediments and/or recent artificial fill.A subsidence has been also revealed in Java over the Yogyakarta urban area. This local displacement is inducedby groundwater exploitation and soft sediment compaction, a result of major urban expansion and human activityduring the last years. The high resolution of COSMO-SkyMed data allows catching

Autore Pugliese

• Refice Alberto , Bovenga Fabio

Tutti gli autori

• F. Bovenga; A. Ganas; A. Refice; A. Belmonte ; R. Nutricato; D. O. Nitti; M. T. Chiaradia; S. Valkaniotis; S. Gkionic; C. Kosma; P. Manunta; Elizar; Darusman; P. Bally

Titolo volume/Rivista

Geophysical research abstracts

Anno di pubblicazione

2018

ISSN

1607-7962

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

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Numero di citazioni Scopus

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Settori ERC

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Codici ASJC

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