Land subsidence detection in Jakarta Province using Sentinel-1A Satellite Imagery

The land surface in Jakarta Province is thought to have experienced relatively continuous subsidence because of natural processes and artificial activities. This research was carried out to evaluate the rate of land subsidence in Jakarta Province. Based on this research, it can be shown from the Sentinel-1A satellite images that there has been landed subsidence. The data used are two pairs of Sentinel-1A Single Looking Complex (SLC) images acquired in 2019 and 2020. The data was processed using the DInSAR method to examine the rate of land subsidence. The results show that the land subsidence rate in Jakarta Province during the 2019-2020 period varies from 1.8 cm to -10.7 cm/year. The literature data results in 2016 experienced a decrease in land subsidence with a significant value of -12.6 cm/year. Land subsidence in 2017 averaged -1.8 cm/year. The land subsidence results from 2019 to 2020 have a value that tends to be lower than in 2016 of - 3.62 cm/year. Land subsidence occurs mostly in coastal areas and near estuaries caused by the nature of alluvial deposition materials. It has caused damages to road infrastructure in several regions of Jakarta Province, such as Mutiara Beach, West Cengkareng, and Pademangan.

Land Subsidence Detection in Jakarta Province Using Sentinel-1A Satellite Imagery

<p>The land surface in DKI Jakarta Province is thought to have experienced relatively continuous subsidence because of natural processes and man-made activities. This research was carried out to evaluate the rate of land subsidence in Jakarta Province. The data used in this study are two pairs of Sentinel-1A level 1 Single Looking Complex (SLC) images which were acquired in 2019 and 2020. The data was processed using the DInSAR method to examine the rate of land subsidence.  The results show that the land subsidence rate in Jakarta Province during the 2019-2020 period varies from 1.8 cm to -10.7 cm/year. From 2019 to 2020, the average land subsidence in the City of North Jakarta is around –4.9 cm/year, East Jakarta is around –2.5 cm/year, West Jakarta is around –4.8 cm/year, Central Jakarta is around –3.1 cm/year, and South Jakarta about –2.8 cm/year. Land subsidence occurs mostly in coastal areas and near estuaries caused by the nature of alluvial deposition materials. It has caused damages to road infrastructure in several regions of Jakarta Province, such as Mutiara Beach, West Cengkareng, and Pademangan.</p><p> </p><p>Keywords: coastal areas, DInSAR, land subsidence, satellite imagery, Sentinel-1A</p>

Archaeology and ethnography demonstrate a human origin for Amazonian Dark Earths

Archaeological research provides clear evidence that the widespread formation of Amazonian Dark Earths (ADEs) in tropical lowland South America was concentrated in the Late Holocene, an outcome of sharp demographic growth that peaked towards 1000 BP. In their recent paper, however, Silva et al. propose that the high fertility of ADE is not of anthropic origin but instead the result of alluvial deposition starting in the Middle Holocene (8200-4200 cal BP). In order to support this argument, they marshal data and observations from a single expanse of ADE, the archaeological site of Caldeirão, and disregard or misread other studies of ADEs in the Central Amazon region. Silva et al.'s claim, an epilogue to ‘geogenic’ models laid to rest over 40 years ago, also dismisses research showing how long-term anthropic soil enrichment occurs as a result of daily practices at contemporary indigenous settlements. Here we critically review Silva et al.’s analysis and affirm that, like most ADEs, Caldeirão has anthropic soil horizons formed by burning, deposition, and reworking of refuse associated with indigenous settlement activities between 2500 and 500 BP.

Stratigraphy and sedimentology of distal-alluvial and lacustrine deposits of the western-central Ebro Basin (NE Iberia) reflecting the onset of the middle Miocene Climatic Optimum

Stratigraphic and sedimentological study of distal alluvial and lacustrine deposits in the Plana de la Negra-Sancho Abarca area (western-central Ebro Basin, NE Iberia) within the early and middle Miocene allows five main lithofacies to be characterized and mapped within two tectosedimentary units, construction of a sedimentary facies model and discussion on allogenic controls on sedimentation. In this area, the boundary between tectosedimentary units T5 and T6 appears to be conformable and is marked by the change from dominant clastics to carbonates. Correlation of the studied outcrops with nearby sections that already had magnetostratigraphic and biostratigraphic data allows the studied succession to be dated from C5Dr to C5Cn (Burdigalian-Langhian), placing the boundary T5/T6 at ca. 16.1-16.05Ma. Seven vertical facies sequences document deposition of distal alluvial clastics and palustrine and lacustrine carbonates. Sandstones and mudstones represent low-sinuosity channels and lateral and terminal splays by unconfined flows runnig across the alluvial plain, associated to the Pyrenean-derived Luna fluvial system. The carbonates contain charophytes, ostracods, bivalves and gastropods, indicating deposition in 2-4m deep lakes. Laminated carbonate facies record reworking of shore carbonates and the influx fine-siliciclastic sediment offshore. Abundant bioturbation and desiccation features indicate episodic submergence and subaerial exposure. Four main episodes of alluvial and associated palustrine/lacustrine facies belt shifts are identified. Alluvial deposition in the studied T5 unit is related to low lake level conditions, rather than to a Pyrenean uplift. The maximum extent of the freshwater carbonates occur at the base of unit T6. This is consistent with conditions of increasing humidity of the Middle Miocene Climatic Optimum.

River logjams cause frequent large-scale forest die-off events in southwestern Amazonia

This paper investigates the dynamics of logjam-induced floods and alluvial deposition in the Bolivian Amazon and the effects these have on forest disturbance and recovery cycles. It expands on previous work by Gullison et al. (1996) who reported a case of catastrophic floods triggered by logjams in the Chimane Forest in the Bolivian Amazon. No further studies have followed up on this observation and no research has been published on the effects of large wood in tropical lowland rivers. The study is based on the analysis of a time series of Landsat imagery (1984–2016) and field evidence. Results show that logjam-induced floods are a major driver of forest disturbance along the Andean piedmont in the Bolivian Amazon. New logjams form on an almost yearly basis, always further upriver, until an avulsion takes place. Logjam-induced floods are characterized here by the sudden deposition of a thick sand layer and the death of forest in a V-shaped area. The Bolivian Amazon offers a unique opportunity for further research on how large wood affects river behavior in lowland tropical settings and how large and frequent forest disturbance events resulting from river logjams affect forest biodiversity and community successions.