Excessive pumping of groundwater in the Metro Manila district, the Philippines, has occurred huge land subsidence. The
purpose of this study is to investigate the distribution of spatial and temporal change on the earth surface in this area. We
measured long-term ground subsidence by InSAR using JERS-1/SAR, ENVISAT/ASAR, Fine-beam, polarimetry and
ScanSAR mode of ALOS/PALSAR, and TerraSAR-X data. As a result, we detected apparent subsidence and uplift
patterns at eight locations. They have been found to correlate with up-down motion of groundwater level. The largest
amount of ground subsidence was measured approximately 600 mm over 6 years (100mm/year).
In this study, we applied InSAR time series analysis using PALSAR and TerraSAR-X data to Zonguldak Hardcoal Basin
in Republic of Turkey in order to monitor mining induced surface displacement. Zonguldak coal area is located along the Black Sea 240 km eastward from Istanbul. Recently, ground deformation caused by underground exploration has come to the surface, and it has been destroying roads and buildings. We utilized PALSAR and TerraSAR-X data for the detail analysis on the recent land subsidence induced by mining activities. PALSAR data in the fine beam mode were obtained from an ascending orbit, TerraSAR-X data in the StripMap mode were from a descending orbit. The vertical and the east-west displacement were calculated by the composition of the deformation vectors of PALSAR and TerraSAR-X. Additionally, the source depth of the main anomaly detected near the campus of Zonguldak Karaelmas University (ZKU) was estimated by vector analysis using the vertical and east-west displacement. As a result, it was approximately 80 to 100 meters under the sea level. On the other hand, the depth of coal production zones is recorded 300 to 560 meters under the sea level. Thus, it was supposed that the anomaly near the university had been caused by not only mining activities but also the other factor in the shallower geological formation. Because some historical documents said that some caves existed in the limestone formation bedded over coal formations and domestic wastewater is injected into these caves, perhaps the cause of land subsidence is considered the expansion of caves’ space resulted from the solution of limestone rocks by the wastewater injection.
North Anatolian Fault (NAF) has several records of a huge earthquake occurrence in the last one century, which is well-known
as a risky active fault. Some signs indicating a creep displacement could be observed on the Ismetpasa segment.
It is reported so far that the San Andreas Fault in California, the Longitudinal Valley fault in Taiwan and the Valley Fault
System in Metro Manila also exhibit fault creep. The fault with creep deformation is aseismic and never generates the
large-scale earthquakes. But the scale and rate of fault creep are important factors to watch the fault behavior and to
understand the cycle of earthquake.
The purpose of this study is to investigate the distribution of spatial and temporal change on the ground motion due to
fault creep in the surrounding of the Ismetpasa, NAF. DInSAR is capable to catch a subtle land displacement less than a
centimeter and observe a wide area at a high spatial resolution. We applied InSAR time series analysis using PALSAR
data in order to measure long-term ground deformation from 2007 until 2011. As a result, the land deformation that the
northern and southern parts of the fault have slipped to east and west at a rate of 7.5 and 6.5 mm/year in line of sight
respectively were obviously detected. In addition, it became clear that the fault creep along the NAF extended 61 km in
east to west direction.
Interferometric Synthetic Aperture Radar (InSAR), one of typical application techniques of SAR data, is used to generate Digital Elevation Model (DEM) while it is also used to measure spatial surface deformation. The former and the later techniques are usually differentiated as InSAR and Differential InSAR respectively. In this paper, we focus the later technique as InSAR. We measured ground deformation using automatic InSAR processing and verified accuracy of obtained results. The study area is Zonguldak coalfield, located along the Black Sea coast approximately 240 kilometer away from Istanbul to the east, Republic of Turkey. In this region, underground coal mining has been undergoing since 1848 and 3 million ton per year of hard coal has been produced. Recently, this coal mining is found to be causing subsidence around this area. Since the whole damage has not been grasped, we tried to measure the amount of surface deformation using InSAR. As a result, some phase anomalies were detected just above mining drifts, and the largest deformation amounts among those was 204 millimeter per 4.5 months in slant range direction. In addition, InSAR results are corresponded with GPS measurement results within 9 millimeter variations.