Some Insights into Topographic, Elastic and Self-gravitation Interaction in Modelling Ground Deformation and Gravity Changes in Active Volcanic Areas

Charco, María; Fernández, José; Luzón, Francisco; Tiampo, K. F.; Rundle, John B.

doi:10.1007/s00024-004-0190-y

Cited by 11 publications

(3 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Prominence contributes to a flattening of the peak magnitude of both observables, with the largest impact at Erciyes Dağ noted directly over the summit where the slope angle is greatest (Figures 5, 6). These findings broadly corroborate results from axisymmetric models presented in Cayol and Cornet (1998) and Charco et al (2007) and attest to the importance of considering topography for interpreting data from large-prominence volcanoes.…”

Section: The Effect Of Topographysupporting

confidence: 86%

Minimum Detectable Mass and Volume Fluxes During Magmatic Recharge at High Prominence Volcanoes: An Application to Erciyes Dağ Volcano (Turkey)

Males

Gottsmann

2021

Front. Earth Sci.

View full text Add to dashboard Cite

Magma reservoir recharge is widely recognised as a precursor of eruptive activity. However, the causative relationships between reservoir rejuvenation and surface observables such as gravitational potential field changes and ground deformation are still poorly understood. At intermediate and silicic intra-plate volcanoes where crustal mechanical heterogeneity combined with high-prominence are expected to fundamentally affect the crustal stress and strain relationship, protracted period of repose and absence of monitoring data raise questions about the detectability of magma recharge. Here we report results from integrated geodetic forward modelling of ground displacements and gravity changes from reservoir recharge at Erciyes Dağ, a large prominence (∼2,800 m), yet poorly studied, stratovolcano of the Central Anatolian Volcanic Province in Turkey. The most recent eruption at ∼7000 BC, close proximity to the Kayseri Metropolitan Area and absence of dedicated volcano monitoring set a precedent to explore stealth magmatic processes at the volcano. Using finite element analysis we systematically explore the influence of subsurface mechanical heterogeneities and topography on surface deformation and gravity changes from magmatic recharge of Erciyes Dağ’s reservoir. We show that whilst crustal heterogeneity amplifies ground displacements and gravity variations, the volcano’s substantial prominence has the opposite effect. For generic reservoir pressure and density changes of 10 MPa and 10 kg m−3 predicted vertical displacements vary by a factor of 5 while residual gravity changes vary by a factor of 12 between models ignoring topography or mechanical heterogeneity and those that do not. We deduce reservoir volume and mass changes of order 10–3 km3 and 1010 kg, respectively, at the detectability limit of conventional surveying techniques at the volcano. Though dependent on model assumptions, all results indicate that magma recharge at Erciyes Dağ may go undetected at fluxes 1) sufficient to maintain an active reservoir containing eruptable magma and 2) similar to those reported for intermediate/silicic volcanoes with repose times of 100–1,000s of years (e.g., Parinacota) and persistently active mafic volcanoes such as Mt. Etna and Stromboli. Our findings may be utilised to inform integrated geodetic and gravimetric monitoring at Erciyes Dağ and other large prominence silicic volcanoes and could provide early insights into reservoir rejuvenation with implications for the development of disaster risk reduction initiatives.

show abstract

Section: The Effect Of Topographysupporting

confidence: 86%

Minimum Detectable Mass and Volume Fluxes During Magmatic Recharge at High Prominence Volcanoes: An Application to Erciyes Dağ Volcano (Turkey)

Males

Gottsmann

2021

Front. Earth Sci.

View full text Add to dashboard Cite

show abstract

“…The main difference between real and approximate topography consideration is the pattern of the gravity variation. Horizontal coordinates for panels ͑b͒ through ͑f͒ are UTM coordinates in meters ͑modi-fied from Charco et al, 2007a͒.…”

Section: The Effects Of Heterogeneitiesmentioning

confidence: 99%

4D volcano gravimetry

Gottsmann²,

et al. 2008

Self Cite

View full text Add to dashboard Cite

Time-dependent gravimetric measurements can detect subsurface processes long before magma flow leads to earthquakes or other eruption precursors. The ability of gravity measurements to detect subsurface mass flow is greatly enhanced if gravity measurements are analyzed and modeled with ground-deformation data. Obtaining the maximum information from microgravity studies requires careful evaluation of the layout of network benchmarks, the gravity environmental signal, and the coupling between gravity changes and crustal deformation. When changes in the system under study are fast ͑hours to weeks͒, as in hydrothermal systems and restless volcanoes, continuous gravity observations at selected sites can help to capture many details of the dynamics of the intrusive sources. Despite the instrumental effects, mainly caused by atmospheric temperature, results from monitoring at Mt. Etna volcano show that continuous measurements are a powerful tool for monitoring and studying volcanoes.Several analytical and numerical mathematical models can beused to fit gravity and deformation data. Analytical models offer a closed-form description of the volcanic source. In principle, this allows one to readily infer the relative importance of the source parameters. In active volcanic sites such as Long Valley caldera ͑California, U.S.A.͒ and Campi Flegrei ͑Italy͒, careful use of analytical models and high-quality data sets has produced good results. However, the simplifications that make analytical models tractable might result in misleading volcanological interpretations, particularly when the real crust surrounding the source is far from the homogeneous/isotropic assumption. Using numerical models allows consideration of more realistic descriptions of the sources and of the crust where they are located ͑e.g., vertical and lateral mechanical discontinuities, complex source geometries, and topography͒. Applications at Teide volcano ͑Tenerife͒ and Campi Flegrei demonstrate the importance of this more realistic description in gravity calculations.

show abstract

“…Moreover, the mathematical model for the source structure must consider some elastic properties to account for the deformation phenomena. The usual analytical models assume an elastic, homogeneous and isotropic crust, but they can take into account effects from several source geometries, topography relief, and gravity background [e.g., Williams and Wadge , 1998; Charco et al , 2007; Battaglia and Hill , 2009]. The elastic‐gravitational model of Rundle [1980, 1982] and Fernández and Rundle [1994a, 1994b] is a refinement of purely elastic models and can interpret gravity and deformation changes in active volcanic zones [ Charco et al , 2006].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous inversion of surface deformation and gravity changes by means of extended bodies with a free geometry: Application to deforming calderas

Camacho¹,

González

Fernández³

et al. 2011

J. Geophys. Res.

Self Cite

View full text Add to dashboard Cite

Changes in gravity and/or surface deformation are often associated with volcanic activity. Usually, bodies with simple geometry (e.g., point sources, prolate or oblate spheroids) are used to model these signals considering anomalous mass and/or pressure variations. We present a new method for the simultaneous, nonlinear inversion of gravity changes and surface deformation using bodies with a free geometry. Assuming simple homogenous elastic conditions, the method determines a general geometrical configuration of pressure and density sources. These sources are described as an aggregate of pressure and density point sources, fitting the whole data set (given some regularity conditions). The approach works in a growth step‐by‐step process that allows us to build very general geometrical configurations. The methodology is validated against an ellipsoidal body with anomalous pressure and a parallelepiped body with anomalous density, buried in an elastic medium. The simultaneous inversion of deformation and gravity values permits a good reconstruction of the assumed bodies. Finally, the inversion method is applied to the interpretation of gravity, leveling, and interferometric synthetic aperture radar (InSAR) data from the volcanic area of Campi Flegrei (Italy) for the period 1992–2000. For this period, a model with no significant mass change and an extended decreasing pressure region satisfactorily fits the data. The pressure source is located at about ∼1500 m depth, and it is interpreted as corresponding to the dynamics of the shallow (depth 1–2 km) hydrothermal system confined to the caldera fill materials.

show abstract

Some Insights into Topographic, Elastic and Self-gravitation Interaction in Modelling Ground Deformation and Gravity Changes in Active Volcanic Areas

Cited by 11 publications

References 29 publications

Minimum Detectable Mass and Volume Fluxes During Magmatic Recharge at High Prominence Volcanoes: An Application to Erciyes Dağ Volcano (Turkey)

Minimum Detectable Mass and Volume Fluxes During Magmatic Recharge at High Prominence Volcanoes: An Application to Erciyes Dağ Volcano (Turkey)

4D volcano gravimetry

Simultaneous inversion of surface deformation and gravity changes by means of extended bodies with a free geometry: Application to deforming calderas

Contact Info

Product

Resources

About