Volcanic structures investigation through SAR and seismic interferometric methods: The 2011–2013 Campi Flegrei unrest episode

Pepe, Susi; Siena, Luca De; Barone, Andrea; Castaldo, Raffaele; D’Auria, Luca; Manzo, M.; Casu, Francesco; Fedi, Maurizio; Lanari, R.; Bianco, Francesca; Tizzani, Pietro

doi:10.1016/j.rse.2019.111440

Cited by 29 publications

(38 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, the major uncertainty in this work may come from our assumptions in the fault geometry as well as architecture and fault mechanical properties, which may be more complex in natural faults in volcanic regions (Cappa & Rutqvist, 2011). Future research must tackle a more accurate 3D description of the shallow lithological changes, for example, including tomographically described models that suggest the importance of lateral intrusions and vertical tectonic lineaments when modeling fluid propagation (De Siena, Sammarco, et al., 2018; Pepe et al., 2019; Siniscalchi et al., 2019). We have carefully summarized in Supporting Information (Figure S5) the influence of each of the variables or factors discussed above on the fault displacements and respective magnitudes of seismicity based on our observations and deductions from the results of Scenarios A, C, and D to aid comparison between the HM and THM effects in this work.…”

Section: Discussionmentioning

confidence: 99%

“…Velocity and attenuation tomography studies have recently located the horizons and lateral extension of this caprock (Akande, De Siena, et al, 2019;Calò & Tramelli, 2018;De Siena, Amoruso, et al, 2017;De Siena, Chiodini, et al, 2017;De Siena, Sammarco, et al, 2018). Resistivity, seismic, and deformation models of the caldera during recent unrests recognize the combined action of the caprock, preexisting tectonic lineaments and historical intrusions in constraining the flow between the basal reservoir and the outflow zone (De Siena, Sammarco, et al, 2018;Pepe et al, 2019;Siniscalchi et al, 2019). This level of detail on volcanic structures makes CFc the ideal laboratory to simulate the seismic response to fluid injections during volcanic unrests.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Thermo‐Hydro‐Mechanical Model and Caprock Deformation Explain the Onset of an Ongoing Seismo‐Volcanic Unrest

et al. 2021

View full text Add to dashboard Cite

Modeling seismicity at volcanoes remains challenging as the processes that control seismic energy release due to fluid transport, heat flow, and rock deformation are firmly coupled in complex geological media. Here, we couple fluid‐flow and mechanical (deformation) simulators (TOUGHREACT–FLAC3D) to reproduce fluid‐induced seismicity at Campi Flegrei caldera (southern Italy) in isothermal (HM) and nonisothermal (THM) conditions. The unique ability of the Campi Flegrei caprock to withstand stress induced by hot‐water injections is included in the model parametrization. After pore pressure accumulation is guided by a combination of thermal and hydromechanical interactions, contrasting compressive and extensional forces act on the basal and top parts of the caprock, respectively. Then, pressure perturbation and caprock deformation induce fractures that allow hot fluids uprising to pressurize the overlying fault, driving it toward failure and triggering seismicity. Under similar mechanical boundary conditions, the induced thermal effects prompt seismic slip earlier but with higher seismic magnitudes when (1) thermal equilibrium is preserved and (2) the thermal contrast is enhanced due to increased fluid injection temperatures. The results indicate that numerical models of volcano seismicity must consider the influence of rock‐sealing formations to obtain more robust, accurate, and realistic seismic predictions at volcanoes. The proposed models satisfactorily reproduce the magnitude–depth distribution of the swarm (October 5, 2019), preceding the two strongest earthquakes recorded in 35 years at the caldera (3.1 and 3.3—on December 6, 2019, and April 26, 2020, respectively) using hot‐water injection from depth.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Thermo‐Hydro‐Mechanical Model and Caprock Deformation Explain the Onset of an Ongoing Seismo‐Volcanic Unrest

et al. 2021

View full text Add to dashboard Cite

show abstract

“…By defining f ( x , y , z ) as a spatially regularized field referred to a constant Z‐level, the THD technique consists in the analysis of the spatial distribution of the maxima of the horizontal gradient magnitude computed on f ( x , y , z ) as:

THD = \sqrt{{(\frac{\partial f (x, y, z)}{\partial x})}^{2} + {(\frac{\partial f (x, y, z)}{\partial y})}^{2}},

where the horizontal derivatives are calculated through simple finite‐difference relationship; the retrieved distribution depends on the field source geometry since its maxima occur where the considered physical property has the greatest variation, that is, at the boundaries of the sources (Pepe et al., 2019).…”

Section: Collected Datamentioning

confidence: 99%

“…In the volcanic context, the THD technique represents an employable tool for defining the geometries of both volcanic bodies and discontinuities; for example, boundary analysis techniques have highlighted the volcanic structures at Campi Flegrei caldera starting from gravity (Florio et al., 1999), aeromagnetic, (Fedi & Florio, 2001) and vertical deformation data (Pepe et al., 2019). The proposed methodology is based on the concept that the highest variations in the physical properties of the medium we can measure (i.e., rigidity) occur at discontinuities within the crust, or the boundary between a magmatic reservoir and crustal rocks.…”

Section: Collected Datamentioning

confidence: 99%

A Novel Multidisciplinary Approach for the Thermo‐Rheological Study of Volcanic Areas: The Case Study of Long Valley Caldera

et al. 2021

Self Cite

View full text Add to dashboard Cite

The Long Valley caldera formed 0.760 Ma ago, as a result of a paroxysmal Bishop Tuff eruption. This event released 650-700 km 3 of gas-rich rhyolitic magma and drove the caldera collapse (Bailey, 1989; Carle, 1988; Hildreth & Wilson, 2007). Nowadays, the caldera has roughly an elliptical shape (∼17 km by 31 km) and hosts a magmatic-hydrothermal system which manifests itself at surface as hot springs and fumaroles. Geothermal facilities near the Casa Diablo locality supply 40 MW e from three binary power plants, exploiting ∼850 kg s −1 of 160-180°C water that circulates within the volcanic sediments, having depths spanning from 200 m to 350 m (Campbell, 2000). Since geothermal exploration began in 1960s the understanding of the geothermal system has continuously improved. Moreover, after the occurrence of the May 1980 earthquake swarm (D. P. Hill et al., 2017) many geological, geochemical, and geophysical studies focused on this area. The earthquakes were linked to a ∼0.25 m uplift of the old resurgent dome, located in the central part of the caldera (Battaglia et al., 1999; Tizzani et al., 2007, 2009). The seismic swarms and the inflation of the resurgent dome continue to date. Nowadays its center is ∼0.80 m higher. The seismic activity is associated with changes in discharge rates of hot springs and fumaroles in the southern and eastern sectors of the caldera, as well as with increased CO 2 emissions around Mammoth Mt. (at the southwestern border of the present-day caldera rim; Rogie et al., 2001; Sorey & Clark, 1981). These critical events leading to the creation of a multi-parameter monitoring network (managed by USGS), which in turn delivered the data through periodic public reports and monographies (e.g.

show abstract

“…2b). Here, shear-wave-splitting anisotropy 39 , InSAR 11 , and gravity gradiometry 33 identify a SN anomaly that accumulates the highest lateral stress during unrest 10 , producing small-magnitude earthquakes 31 (Fig 2b,diamonds).…”

mentioning

confidence: 92%

Fluid migrations and volcanic earthquakes from depolarized ambient noise

Siena

Petrosino²

2021

Preprint

View full text Add to dashboard Cite

Ambient noise polarizes inside low-velocity fault zones, yet the spatial and temporal resolution of polarized noise on gas-bearing fluids migrating through stressed volcanic systems is unknown. Pressurized fluids increase stress and lead to volcanic earthquakes; imaging their location in real time would be a giant leap toward forecasting eruptions and monitoring volcanic unrest. Here, we show that depolarized noise detects fluid injections and migrations leading to earthquakes inside the laterally-stressed hydrothermal systems of Campi Flegrei caldera (Southern Italy). A polarized transfer structure connects the deforming centre of the caldera to open hydrothermal vents and extensional caldera-bounding faults during periods of low seismic release. Fluids depolarize the transfer structure and pressurize the hydrothermal system, building up stress before earthquakes and migrating after seismic sequences. During sequences, fluid migration pathways connect the location of the last eruption (Monte Nuovo, 1538AD) with the part of the eastern caldera trapped between transfer and extensional structures. After recent intense seismicity (December 2019-April 2020), the transfer structure appears sealed while fluids stored in the east caldera have moved further east. Depolarized noise has the potential to monitor fluid migrations and earthquakes at stressed volcanoes quasi-instantaneously and with minimum processing.

show abstract

Volcanic structures investigation through SAR and seismic interferometric methods: The 2011–2013 Campi Flegrei unrest episode

Cited by 29 publications

References 64 publications

Thermo‐Hydro‐Mechanical Model and Caprock Deformation Explain the Onset of an Ongoing Seismo‐Volcanic Unrest

Thermo‐Hydro‐Mechanical Model and Caprock Deformation Explain the Onset of an Ongoing Seismo‐Volcanic Unrest

A Novel Multidisciplinary Approach for the Thermo‐Rheological Study of Volcanic Areas: The Case Study of Long Valley Caldera

Fluid migrations and volcanic earthquakes from depolarized ambient noise

Contact Info

Product

Resources

About