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Land subsidence in the Cerro Prieto Geothermal Field, 1 Baja California, Mexico, from 1994 to 2005. An integrated analysis of DInSAR, levelingand geological data.
Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994- 1997 and 1997-2006) and detailed geological information in order to improve the understanding of temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the spatial pattern of the subsidence as well as changes in rate are highly correlated with the development of the Cerro Prieto Geothermal Field
Causes of unrest at silicic calderas in the East African Rift: new constraints from InSAR and soil-gas chemistry at Aluto volcano, Ethiopia
This work is a contribution to the Natural Environment Research Council (NERC) funded RiftVolc project (NE/L013932/1, Rift volcanism: past, present, and future). W.H., J.B., T.A.M., and D.M.P. are supported by and contribute to the NERC Centre for the Observation and Modelling of Earthquakes, Volcanoes, and Tectonics (COMET). Envisat data were provided by ESA. ALOS data were provided through ESA third party mission. W.H. funded by NERC studentship, NE/J5000045/1. Additional funding for fieldwork was provided by University College (University of Oxford), the Geological Remote Sensing Group, the Edinburgh Geological Society, and the Leverhulme Trust. Analytical work at the University of New Mexico was supported by the Volcanic and Geothermal Volatiles Lab at the Center for Stable Isotopes and an NSF grant EAR-1113066 to T.P.F.Restless silicic calderas present major geological hazards, and yet many also host significant untapped geothermal resources. In East Africa this poses a major challenge, although the calderas are largely unmonitored their geothermal resources could provide substantial economic benefits to the region. Understanding what causes unrest at these volcanoes is vital for weighing up the opportunities against the potential risks. Here we bring together new field and remote sensing observations to evaluate causes of ground deformation at Aluto, a restless silicic volcano located in the Main Ethiopian Rift (MER). Interferometric Synthetic Aperture Radar (InSAR) data reveal the temporal and spatial characteristics of a ground deformation episode that took place between 2008 and 2010. Deformation time-series reveal pulses of accelerating uplift that transition to gradual long-term subsidence, and analytical models support inflation source depths of ∼5 km. Gases escaping along the major fault zone of Aluto show high CO2 flux, and a clear magmatic carbon signature (CO2–δ13C of −4.2 to −4.5 ‰). This provides compelling evidence that the magmatic and hydrothermal reservoirs of the complex are physically connected. We suggest that a coupled magmatic-hydrothermal system can explain the uplift-subsidence signals. We hypothesize that magmatic fluid injection and/or intrusion in the cap of the magmatic reservoir drives edifice wide inflation while subsequent deflation is related to magmatic degassing and depressurization of the hydrothermal system. These new constraints on the plumbing of Aluto yield important insights into the behaviour of rift volcanic systems and will be crucial for interpreting future patterns of unrest.Publisher PDFPeer reviewe
Spatio-temporal evolution of aseismic ground deformation in the Mexicali Valley (Baja California, Mexico) from 1993 to 2010, using differential SAR interferometry
Ground deformation in Mexicali Valley, Baja California, Mexico, the southern
part of the Mexicali-Imperial valley, is influenced by active tectonics and
human activity, mainly that of geothermal fluid extraction in the Cerro
Prieto Geothermal Field. Significant ground deformation, mainly subsidence
(~ 18 cm yr−1), and related ground fissures cause severe damage
to local infrastructure.
The technique of Differential Synthetic Aperture Radar Interferometry
(DInSAR) has been demonstrated to be a very effective remote sensing tool
for accurately measuring the spatial and temporal evolution of ground
displacements over broad areas. In present study ERS-1/2 SAR and ENVISAT
ASAR images acquired between 1993 and 2010 were used to perform a historical
analysis of aseismic ground deformation in Mexicali Valley, in an attempt to
evaluate its spatio-temporal evolution and improve the understanding of its
dynamic. For this purpose, the conventional 2-pass DInSAR was used to
generate interferograms which were used in stacking procedure to produce
maps of annual aseismic ground deformation rates for different periods.
Differential interferograms that included strong co-seismic deformation
signals were not included in the stacking and analysis.
The changes in the ground deformation pattern and rate were identified. The
main changes occur between 2000 and 2005 and include increasing deformation
rate in the recharge zone and decreasing deformation rate in the western
part of the CPGF production zone. We suggested that these changes are mainly
caused by production development in the Cerro Prieto Geothermal Field
Land Subsidence Detection in the Coastal Plain of Tabasco, Mexico Using Differential SAR Interferometry
Land subsidence (LS) increases flood vulnerability in coastal areas, coastal plains, and river deltas. The coastal plain of Tabasco (TCP) has been the scene of recurring floods, which caused economic and social damage. Hydrocarbon extraction is the main economic activity in the TCP and could be one of the causes of LS in this region. This study aimed to investigate the potential of differential SAR interferometric techniques for LS detection in the TCP. For this purpose, Sentinel-1 SLC descending and ascending images from the 2018–2019 period were used. Conventional DInSAR, together with the differential interferograms stacking (DIS) approach, was applied. The causes of interferometric coherence degradation were analyzed. In addition, Sentinel-1 GRD images were used for delimitation of areas recurrently affected by floods. Based on the results of the interferometric processing, several subsiding zones were detected. The results indicate subsidence rates of up to −6 cm/yr in the urban centers of Villahermosa, ParaÃso, Comalcalco, and other localities. The results indicate the possibility of an influence of LS on the flood vulnerability of the area south of Villahermosa city. They also suggest a possible relationship between hydrocarbon extraction and surface deformation
Land Subsidence Detection in the Coastal Plain of Tabasco, Mexico Using Differential SAR Interferometry
Land subsidence (LS) increases flood vulnerability in coastal areas, coastal plains, and river deltas. The coastal plain of Tabasco (TCP) has been the scene of recurring floods, which caused economic and social damage. Hydrocarbon extraction is the main economic activity in the TCP and could be one of the causes of LS in this region. This study aimed to investigate the potential of differential SAR interferometric techniques for LS detection in the TCP. For this purpose, Sentinel-1 SLC descending and ascending images from the 2018–2019 period were used. Conventional DInSAR, together with the differential interferograms stacking (DIS) approach, was applied. The causes of interferometric coherence degradation were analyzed. In addition, Sentinel-1 GRD images were used for delimitation of areas recurrently affected by floods. Based on the results of the interferometric processing, several subsiding zones were detected. The results indicate subsidence rates of up to −6 cm/yr in the urban centers of Villahermosa, Paraíso, Comalcalco, and other localities. The results indicate the possibility of an influence of LS on the flood vulnerability of the area south of Villahermosa city. They also suggest a possible relationship between hydrocarbon extraction and surface deformation
Using ALOS PALSAR derived high-resolution DInSAR to detect slow-moving landslides in tropical forest: Cameron Highlands, Malaysia
Subsidence monitoring with geotechnical instruments in the Mexicali Valley, Baja California, Mexico
The Mexicali Valley (northwestern Mexico), situated in the southern part of
the San Andreas fault system, is an area with high tectonic deformation,
recent volcanism, and active seismicity. Since 1973, fluid extraction, from
the 1500–3000 m depth range, at the Cerro Prieto Geothermal Field (CPGF),
has influenced deformation in the Mexicali Valley area, accelerating the
subsidence and causing slip along the traces of tectonic faults that limit
the subsidence area. Detailed field mapping done since 1989 (González et
al., 1998; Glowacka et al., 2005; Suárez-Vidal et al., 2008) in the
vicinity of the CPGF shows that many subsidence induced fractures, fissures,
collapse features, small grabens, and fresh scarps are related to the known
tectonic faults. Subsidence and fault rupture are causing damage to
infrastructure, such as roads, railroad tracks, irrigation channels, and
agricultural fields.
Since 1996, geotechnical instruments installed by CICESE (Centro de
Investigación Ciéntifica y de Educación Superior de Ensenada,
B.C.) have operated in the Mexicali Valley, for continuous recording of
deformation phenomena. Instruments are installed over or very close to the
affected faults. To date, the network includes four crackmeters and eight
tiltmeters; all instruments have sampling intervals in the 1 to 20 min range.
Instrumental records typically show continuous creep, episodic slip events
related mainly to the subsidence process, and coseismic slip discontinuities
(Glowacka et al., 1999, 2005, 2010; Sarychikhina et al., 2015).
The area has also been monitored by levelling surveys every few years and,
since the 1990's by studies based on DInSAR data (Carnec and Fabriol, 1999;
Hansen, 2001; Sarychikhina et al., 2011).
In this work we use data from levelling, DInSAR, and geotechnical
instruments records to compare the subsidence caused by anthropogenic
activity and/or seismicity with slip recorded by geotechnical instruments,
in an attempt to obtain more information about the process of fault slip
associated with subsidence