InSAR observations of lake loading at Yangzhuoyong Lake, Tibet: Constraints on crustal elasticity

Zhao, W.; Amelung, F.; Doin, Marie‐Pierre; Dixon, Timothy H.; Wdowinski, S.; Lin, Guoqing

doi:10.1016/j.epsl.2016.05.044

Cited by 17 publications

(17 citation statements)

References 43 publications

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“…The shear modulus applicable for static mechanical models is lower than the shear modulus for seismic waves because of the presence of fluid‐filled pores and cracks (e.g., Gudmundsson, ; Wauthier et al, ; Zhao et al, ). The frequency dependence of the modulus decreases with depth and confining pressure (Ciccotti & Mulargia, ).…”

Section: Application Of Failure Models To Sinabung Agung Westdahl mentioning

confidence: 99%

The Role of Pore Fluid Pressure on the Failure of Magma Reservoirs: Insights From Indonesian and Aleutian Arc Volcanoes

2018

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We use numerical models to study the mechanical stability of magma reservoirs embedded in elastic host rock. We quantify the overpressure required to open tensile fractures (the failure overpressure), as a function of the depth and the size of the reservoir, the loading by the volcanic edifice, and the pore fluid pressure in the crust. We show that the pore fluid pressure is the most important parameter controlling the magnitude of the failure overpressure rather than the reservoir depth and the edifice load. Under lithostatic pore fluid pressure conditions, the failure overpressure is on the order of the rock tensile strength (a few tens of megapascals). Under zero pore fluid pressure conditions, the failure overpressure increases linearly with depth (a few hundreds of megapascals at 5 km depth). We use our models to forecast the failure displacement (the cumulative surface displacement just before an eruption) on volcanoes showing unrest: Sinabung and Agung (Indonesia) and Okmok and Westdahl (Aleutian). By comparison between our forecast and the observation, we provide valuable constraint on the pore fluid pressure conditions on the volcanic system. At Okmok, the occurrence of the 2008 eruption can be explained with a 1,000 m reservoir embedded in high pore fluid pressure, whereas the absence of eruption at Westdahl better suggests that the pore fluid pressure is much lower than lithostatic. Our finding suggests that the pore fluid pressure conditions around the reservoir may play an important role in the triggering of an eruption by encouraging or discouraging the failure of the reservoir.

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Section: Application Of Failure Models To Sinabung Agung Westdahl mentioning

confidence: 99%

The Role of Pore Fluid Pressure on the Failure of Magma Reservoirs: Insights From Indonesian and Aleutian Arc Volcanoes

2018

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“…The amount of ground deformations of a reservoir's surrounding can either be measured on individual points with levelling [2] or Global Navigation Satellite System (GNSS) measurements [3,4] or measured in a spatially continuous manner by means of Differential Synthetic Aperture Radar Interferometry (DInSAR). Thus far, in studies that are based on SAR data, either ERS-1/2 [5,6], Envisat Advanced Synthetic Aperture Radar (ASAR) [7] or a combination of those sensors [8,9] were used to quantify the regional deformation around a lake. Recently, ground deformations due to the water level changes in the Tehri Reservoir in the Himalaya region was investigated with ALOS PALSAR data [10].…”

Section: Introductionmentioning

confidence: 99%

Ground Deformations around the Toktogul Reservoir, Kyrgyzstan, from Envisat ASAR and Sentinel-1 Data—A Case Study about the Impact of Atmospheric Corrections on InSAR Time Series

et al. 2018

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We present ground deformations in response to water level variations at the Toktogul Reservoir, located in Kyrgyzstan, Central Asia. Ground deformations were measured by Envisat Advanced Synthetic Aperture Radar (ASAR) and Sentinel-1 Differential Interferometric Synthetic Aperture Radar (DInSAR) imagery covering the time periods 2004-2009 and 2014-2016, respectively. The net reservoir water level, as measured by satellite radar altimetry, decreased approximately 60 m (∼13.5 km 3) from 2004-2009, whereas, for 2014-2016, the net water level increased by approximately 51 m (∼11.2 km 3). The individual Small BAseline Subset (SBAS) interferograms were heavily influenced by atmospheric effects that needed to be minimized prior to the time-series analysis. We tested several approaches including corrections based on global numerical weather model data, such as the European Centre for Medium-Range Weather Forecasts (ECMWF) operational forecast data, the ERA-5 reanalysis, and the ERA-Interim reanalysis, as well as phase-based methods, such as calculating a simple linear dependency on the elevation or the more sophisticated power-law approach. Our findings suggest that, for the high-mountain Toktogul area, the power-law correction performs the best. Envisat descending time series for the period of water recession reveal mean line-of-sight (LOS) uplift rates of 7.8 mm/yr on the northern shore of the Toktogul Reservoir close to the Toktogul city area. For the same area, Sentinel-1 ascending and descending time series consistently show a subsidence behaviour due to the replenishing of the water reservoir, which includes intra-annual LOS variations on the order of 30 mm. A decomposition of the LOS deformation rates of both Sentinel-1 orbits revealed mean vertical subsidence rates of 25 mm/yr for the common time period of March 2015-November 2016, which is in very good agreement with the results derived from elastic modelling based on the TEA12 Earth model.

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“…We construct sensitivity kernels to constrain the depth of the elastic structure to which the uplift signal is most sensitive following Doin et al () and Zhao et al (). We divide the PREM elastic structure into 5‐km‐thick segments.…”

Section: Resultsmentioning

confidence: 99%

The Importance of the Inelastic and Elastic Structures of the Crust in Constraining Glacial Density, Mass Change, and Isostatic Adjustment From Geodetic Observations in Southeast Alaska

2019

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Elastic deformation of the solid Earth in response to ice mass loss offers a promising constraint on the density of glacial material lost. Further, the elastic response to modern deglaciation is important to constrain for studies of glacial isostatic adjustment to determine the mantle's structure and rheology. Models of this elastic uplift are commonly based on the 1-D, seismically derived global average Preliminary Reference Earth Model and typically neglect uncertainties that can arise from regional differences in elastic structure from that of the global average, lateral heterogeneities within the region, and inelastic behavior of the crust. We quantify these uncertainties using an ensemble of 1-D local elastic structure models and empirical relations for the effects of inelasticity in the upper ∼10 km of the crust. In Southeast Alaska, modeling elastic uplift rates with local elastic structures results in up to a 20-40% difference from those modeled with the Preliminary Reference Earth Model. Although these differences are limited to regions near to ice-covered areas, they are comparable to the differences in uplift rates expected from the loss of firn versus loss of ice. Far from ice-covered areas, where most of the region's GPS observations were made, these differences become insignificant and do not affect previous glacial isostatic adjustment studies in the region. The methods presented here are based on the globally available LITHO1.0 seismic model and open source software, and the approach of using an ensemble of 1-D elastic structures can be easily adapted to other regions around the world.

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InSAR observations of lake loading at Yangzhuoyong Lake, Tibet: Constraints on crustal elasticity

Cited by 17 publications

References 43 publications

The Role of Pore Fluid Pressure on the Failure of Magma Reservoirs: Insights From Indonesian and Aleutian Arc Volcanoes

The Role of Pore Fluid Pressure on the Failure of Magma Reservoirs: Insights From Indonesian and Aleutian Arc Volcanoes

Ground Deformations around the Toktogul Reservoir, Kyrgyzstan, from Envisat ASAR and Sentinel-1 Data—A Case Study about the Impact of Atmospheric Corrections on InSAR Time Series

The Importance of the Inelastic and Elastic Structures of the Crust in Constraining Glacial Density, Mass Change, and Isostatic Adjustment From Geodetic Observations in Southeast Alaska

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