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Ikeda M.,Shikoku Research Institute | Kato S.,Shikoku Research Institute | Nishizaka N.,Shikoku Electrical Power Co. | Ohno Y.,Shikoku Electrical Power Co. | And 2 more authors.
Tectonophysics | Year: 2013

We carried out a magnetotelluric (MT) survey along a profile crossing the Median Tectonic Line (MTL) in western Shikoku, Japan. The MTL is a terrane boundary that formed during the Cretaceous between the Sanbagawa belt, consisting of high pressure/temperature (P/T) metamorphic rocks, and the Ryoke belt of granites and low P/T metamorphic rocks. The MT image shows a zone of remarkably low resistivity, dipping northward at 40°, at the surface coincides with the surface trace of the MTL. The low-resistivity zone probably corresponds to a fluid-filled damaged zone of porous media composed of clay minerals and cracked rocks, formed by repeated faulting of the MTL since Late Cretaceous time. The calculated maximum porosity of the damaged zone is 7.1%, which is clearly higher than that of the non-damaged crystalline rocks. © 2013 Elsevier B.V. Source


Kurita K.,Tokyo Metropolitan College of Industrial Technology | Kinugasa Y.,Association for the Development of Earthquake Prediction | Deguchi T.,Nittetsu Mining Consultants Co. | Rimando R.E.,Institute of Volcanology and Seismology
Advances in Civil Engineering and Building Materials - Selected Peer Reviewed Papers from 2012 2nd International Conference on Civil Engineering and Building Materials, CEBM 2012 | Year: 2012

Buildings and pavements are damaged by ground vertical displacement along the creeping segment of the Marikina Valley fault system (MVFS) on the southern part of Metro Manila, Philippines. To clarify fault creep trigger (e.g., groundwater withdrawal, tectonic), deformation is monitored through repeated leveling surveys. Any short term link between fault displacement and rainfall is also monitored through a continuous creep measurement device installed across one of the sites used for leveling survey. From repeated leveling surveys, the average slip rate since September 1999 to January 2010 ranges from 1.77 cm/y to 2.45 cm/y. Creep acceleration since 2004 is observed in some leveling sites. Continuous creep measurement obtained an average slip rate of 0.01 mm/day (3.65 mm/y) until January 2009. However fault creep at NPC B appears to have stopped even with the coming of the rainy season in May 2009. © 2013 Taylor & Francis Group, London. Source


Deguchi T.,Nittetsu Mining Consultants Co. | Kutoglu H.,Zonguldak Karaelmas University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

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. © 2012 SPIE. Source


Deguchi T.,Nittetsu Mining Consultants Co. | Narita T.,Japan Space Systems
European Space Agency, (Special Publication) ESA SP | Year: 2015

The target area of this study is the Maracaibo sedimentary basin located in the western part of Bolivarian Republic of Venezuela. The full-scale exploration and development for oil resources in Venezuela which was the greatest oil-producing country in South America had begun at the Maracaibo sedimentary basin in the 1910s, and it was a center of the oil product in Venezuela until the 1980s. But, in most of oil fields in the Maracaibo sedimentary basin, there is concern over the drain on recoverable reserves due to deterioration, and the production amount of petroleum in Venezuela has been diminishing these days. Leveling and GPS surveying were carried out in the past, and they revealed that the large-scale subsidence phenomenon of which cumulative subsidence amount was approximately 5 meter had occurred. The authors applied the vertical displacement measurement by InSAR time series analysis using PALSAR data obtained in the Fine-beam and ScanSAR observation mode. As a result, it could be confirmed clear ground deformation in the surrounding of three oil fields (Tia Juana, Lagunillas and Bachaquero) and easily recognized that the areas of phase anomalies detected by this analysis had expanded and the number of interference fringes had increased over time. The annual velocity of vertical ground surface displacement measured by InSAR time series analysis was -51 mm per year, -103 mm per year and -58 mm per year in Tia Juana, Lagunillas and Bachaquero oil field respectively. The tendency that an earth surface shifted towards the center of phase anomalies was detected from the result of the horizontal ground change measurement. It was interpreted from Google Earth and Landsat images that oil-related facilities (mainly bowling stations) were built intensively over the areas where phase anomalies were detected. Therefore, it was inferred that there was a high association between the operation activity of the oil field and ground deformation. In addition, the deterioration is remarkable in the oil fields of the Maracaibo basin and oil production volume has been declining, on the other hand the spatial volume of the ground surface deformation also showed a clear decreasing trend. Source


Deguchi T.,Nittetsu Mining Consultants Co.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

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). © 2014 SPIE. Source

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