Lingyun Ji

Detecting land uplift associated with enhanced oil recovery using InSAR in the Karamay oil field, Xinjiang, China

ABSTRACT Subsurface fluid injection is a well-established technology that is often used for enhanced oil recovery from oil fields. The injection process can often cause deformation due to changes in pore pressure, which can be measured using interferometric synthetic aperture radar (InSAR). In this study, the Karamay oil field in Xinjiang served as an example and an attempt was made to detect subsurface fluid injection-induced ground surface deformation. First, possible deformation was assessed across the entire Karamay oil field during 2006–2010 by stacking multiple interferometric pairs. Then, the spatiotemporal evolution of deformation around well Hei103 was studied using the small baseline subset (SBAS) algorithm. The results suggest that localized deformation at the Karamay oil field was related to oil production. Additionally, subsurface fluid injection caused obvious surface uplift around the Hei103 well region.

The July 11, 1995 Myanmar–China earthquake: A representative event in the bookshelf faulting system of southeastern Asia observed from JERS-1 SAR images

Abstract On July 11, 1995, an Mw 6.8 earthquake struck eastern Myanmar near the Chinese border; hereafter referred to as the 1995 Myanmar–China earthquake. Coseismic surface displacements associated with this event are identified from JERS-1 (Japanese Earth Resources Satellite-1) SAR (Synthetic Aperture Radar) images. The largest relative displacement reached 60xa0cm in the line-of-sight direction. We speculate that a previously unrecognized dextral strike-slip subvertical fault striking NW–SE was responsible for this event. The coseismic slip distribution on the fault planes is inverted based on the InSAR-derived deformation. The results indicate that the fault slip was confined to two lobes. The maximum slip reached approximately 2.5xa0m at a depth of 5xa0km in the northwestern part of the focal region. The inverted geodetic moment was approximately Mwxa0=xa06.69, which is consistent with seismological results. The 1995 Myanmar–China earthquake is one of the largest recorded earthquakes that has occurred around the “bookshelf faulting” system between the Sagaing fault in Myanmar and the Red River fault in southwestern China.

Source Parameters of the 2003–2004 Bange Earthquake Sequence, Central Tibet, China, Estimated from InSAR Data

A sequence of Ms ≥ 5.0 earthquakes occurred in 2003 and 2004 in Bange County, Tibet, China, all with similar depths and focal mechanisms. However, the source parameters, kinematics and relationships between these earthquakes are poorly known because of their moderately-sized magnitude and the sparse distribution of seismic stations in the region. We utilize interferometric synthetic aperture radar (InSAR) data from the European Space Agency’s Envisat satellite to determine the location, fault geometry and slip distribution of three large events of the sequence that occurred on 7 July 2003 (Ms 6.0), 27 March 2004 (Ms 6.2), and 3 July 2004 (Ms 5.1). The modeling results indicate that the 7 July 2003 event was a normal-faulting event with a right-lateral slip component, the 27 March 2004 earthquake was associated with a normal fault striking northeast–southwest and dipping northwest with a moderately oblique right-lateral slip, and the 3 July 2004 event was caused by a normal fault. A calculation of the static stress changes on the fault planes demonstrates that the third earthquake may have been triggered by the previous ones.

Measurement of small co-seismic deformation field from multi-temporal SAR interferometry: application to the 19 September 2004 Huntoon Valley earthquake

ABSTRACT Interferometric synthetic aperture (InSAR) has been widely applied to natural disaster monitoring. However, it has limitations due to the influence of noise sources such as atmospheric and topographic artefacts, data processing errors, etc. In particular, atmospheric effect is one of the most prominent noise sources in InSAR for the monitoring of small magnitude deformations. In this paper, we proposed an efficient multi-temporal InSAR (MTInSAR) approach to measure small co-seismic deformations by minimizing atmospheric anomalies. This approach was applied to investigate the 18 September 2004 earthquake over Huntoon Valley, California, using 13 ascending and 22 descending ENVISAT synthetic aperture radar (SAR) images. The results showed that the co-seismic deformation was ±1.5 and ±1.0 cm in the horizontal and vertical directions, respectively. The earthquake source parameters were estimated using an elastic dislocation source from the ascending and descending acquisitions. The root mean square errors between the observed and modelled deformations were improved by the proposed MTInSAR approach to about 3.8 and 1.8 mm from about 4.0 and 5.2 mm in the ascending and descending orbits, respectively. It means that the MTInSAR approach presented herein remarkably improved the measurement performance of a small co-seismic deformation.

Complex Deformation Monitoring over the Linfen–Yuncheng Basin (China) with Time Series InSAR Technology

The Linfen–Yuncheng basin is an area prone to geological disasters, such as surface subsidence, ground fissuring, fault activity, and earthquakes. For the purpose of disaster prevention and mitigation, Interferometric Synthetic Aperture Radar (InSAR) was used to map ground deformation in this area. After the ground deformation characteristics over the Linfen–Yuncheng basin were obtained, the cross-correlations among regional ground subsidence, fault activity, and underground water level were analyzed in detail. Additionally, an area of abnormal deformation was found and examined. Through time series deformation monitoring and mechanism inversion, we found that the abnormal deformation was related mainly to excessive groundwater exploitation.

Deformation at longyao ground fissure and its surroundings, north China plain, revealed by ALOS PALSAR PS-InSAR

Abstract The Longyao ground fissure (LGF) is the longest and most active among more than 1000 ground fissures on the North China Plain. There have been many studies on the formation mechanism of the LGF, due to its scientific importance and its potential for damage to the environment. These studies have been based on both regional tectonic analysis and numerical simulations. In order to provide a better understanding of the formation mechanism, the deformation of the crack and its surrounding environment should be taken into consideration. In this paper, PS-InSAR technology was employed to assess the ground deformation of LGF and its surrounding area, using L-band ALOS-1 PALSAR images from 2007 to 2011. The characteristics of ground deformation, relationships between fissure activity and surrounding faults and groundwater exploitation were analyzed. This study shows that the north side of Longyao fault (LF) is uplifting while the south side is subsiding. This provides the tectonic conditions responsible for the activity of the ground fissure. Local groundwater exploitation also plays an important role in the development of ground fissures. InSAR observations were modeled to infer the loading depth (-2.8u202fkm) and the slip rate (31.1u202fmm/yr) of LF.

Episodic deformation at Changbaishan Tianchi volcano, northeast China during 2004 to 2010, observed by persistent scatterer interferometric synthetic aperture radar

Abstract Based on ENVISAT ASAR images taken from 2004 to 2010, we obtain the deformation time series of the Changbaishan Tianchi volcano by using persistent scatterer interferometric synthetic aperture radar (PSInSAR) technique. Then, the magma chamber parameters are derived by modeling the PSInSAR deformation field based on a Mogi point source. We draw the following conclusions. First, the magma chamber is located immediately beneath the caldera, with a depth of 9 km below sea level. Second, the Changbaishan Tianchi volcano inflated between August 2006 and August 2008, which may be a result of an episodic magma intrusion event leading to pressurization and a volume increase of the magma chamber. The deformation pattern changed oppositely during August 2008 to June 2010, with maximum subsidence more than 10 mm, which may be caused by magma cooling and crystallization in the crustal chamber. Moreover, the deformation fields consist of several components, including large-scale deformation caused by magmatic activity, the local deformation caused by the active faults, and others. In conclusion, our results indicate that the anomalous activity of the Changbaishan Tianchi volcano is obvious in recent years, providing a basis for further research on monitoring this active volcano to reduce hazards and risks of future eruptions.