Space‐weighted seismic attenuation mapping of the aseismic source of Campi Flegrei 1983–1984 unrest

Siena, Luca De; Amoruso, Antonella; Pezzo, Edoardo Del; Wakeford, Zoë; Castellano, M.; Crescentini, Luca

doi:10.1002/2017gl072507

Cited by 58 publications

(67 citation statements)

References 42 publications

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“…The main vertical discontinuities occurring at shallow and midcrustal depth supported by seismic tomography (Figure a; De Natale et al, ; Zollo et al, ) occur at depth of ~4 and ~8 km and are consistent with the architecture of magmatic plumbing system inferred by petrologic, geochemical, and seismic studies (Figure b; Aster & Meyer, ; Caliro et al, ; D'Antonio, ; De Gori et al, ; De Siena et al, , ; Di Renzo et al, ; Fedi et al, ; Nunziata, ; Pappalardo et al, ; Piochi et al, ; Rapolla et al, ).…”

Section: Magma Movements and Doming In The Last 15 Kasupporting

confidence: 66%

Complex Dome Growth at Campi Flegrei Caldera (Italy) in the Last 15 ka

et al. 2018

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The Campi Flegrei caldera (Italy) is an active volcanic system characterized by significant long‐ and short‐term ground deformation phenomena ranging the maxima values in the central sector of the caldera, where La Starza marine terrace is located. A detailed study of the La Starza provided crucial clues for understanding the resurgence of the central sector of the caldera following the 15‐ka Neapolitan Yellow Tuff eruption. The doming of the caldera floor, marked by two primary episodes of uplift, began soon after the collapse of about 110 m following the eruption. The first doming (15–9.2 ka) occurred as a response to loss of lithostatic loading producing magma influx, possibly regulated by thermal magmatic convection and chaotic movement inside the magma reservoir under the caldera. The calculated ~90 m of structural uplift is the persistent displacement correlated with magma volumes intruded accompanying the contemporaneous volcanic activity. The second episode of uplift (5.5–3.8 ka) produced a ground deformation pattern similar to that measured during recent unrest crises suggesting a stable and shallow (~4‐km deep) source of strain like a sill in an elastic half space. By this geometry and inversion of surface deformation, the volume of intruded material was determined. Simply varying pressure history as input, the time history of the surface deformation was reproduced by using spherical source geometry with a concentric viscoelastic shell 8‐km deep. The satisfactory comparison between the two models is a useful indication for interpreting the current unrest phase at the Campi Flegrei caldera.

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Section: Magma Movements and Doming In The Last 15 Kasupporting

confidence: 66%

Complex Dome Growth at Campi Flegrei Caldera (Italy) in the Last 15 ka

et al. 2018

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“…Otherwise the joint inversion of gravimetric and deformation data 15 suggested the presence of a penny-shaped magma intrusion at about 3 km of depth fed by a deeper magma chamber. Recent studies based on seismic attenuation models 19 , 20 speculated on the presence of an aseismic hot volume at a depth of almost 4 km, which was interpreted as an intrusion occurred during the bradyseismic crisis. Their data support the model of either a caprock or a cooled intrusion acting as a barrier for fluids coming from a deeper magmatic source located below the city of Pozzuoli.…”

Section: Introductionmentioning

confidence: 99%

Anatomy of the Campi Flegrei caldera using Enhanced Seismic Tomography Models

Calò

Tramelli

2018

Sci Rep

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Campi Flegrei caldera (Southern Italy) is a densely inhabited area and suffered several unrest episodes in the last centuries. The dynamic of the caldera is highly debated because of conflicting interpretations. Here we present a detailed reconstruction of the Campi Flegrei structure obtained using the microseismicity recorded during the 1984 unrest. Enhanced Seismic Tomography models obtained with these data allow us describing seismic velocities, attenuation, and scattering patterns. Results show: (1) a plumbing system with a diameter of 1 km located between 2.3 km and 4 km depth (2) a 0.5 km thick caprock located at 2 km depth interpreted as the main structure regulating the fluid interchange between deep and shallow sectors of the caldera, (3) the shape and volume of a shallow reservoir beneath the city of Pozzuoli; this reservoir played a key role during the 1982–1984 unrest, (4) several small reservoirs beneath the main craters of the caldera. All these features fit into the debated question on magmatic or hydrothermal mechanism driving the caldera deformation resulting of crucial importance to allow a better assessment of the hazard.

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“…Thus, even being presented general interpretations, we do not discard limitations of the techniques and dataset used, neither the methods implemented, which could inhibit a precise identification of underlying processes. Future works should board these issues, including the proper mapping of the multiple scattering, depth-dependence of the seismic scattering, anisotropy, and depth/thickness of the main seismic discontinuities on the thermal estimations (Margerin, 2017;De Siena et al, 2017;Del Pezzo et al, 2018;Sanborn and Cormier, 2018).…”

Section: Uncertainties and Other Considerationsmentioning

confidence: 99%

Estimation of the Thermal Structure Beneath the Volcanic Arc of the Northern Andes by Coda Wave Attenuation Tomography

2019

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In the Northern Andes, the magmatic arc rises from a broad area of active volcanism in the South, at the border between Ecuador and Colombia, to a linear north-directed trend of active and inactive volcanic cones. A ∼240-km-long west-east-striking slab tear (Caldas Tear) located approx. 5.5 • N creates an offset in the volcanic arc. This tear looks like a significant controller of volcanic activity: its quasi-WE structure separates inactive magmatic bodies of late Miocene age or older in the North from Quaternary magmatic activity in the South. Coda wave attenuation tomography applied on seismic waveforms recorded between 1993 and 2018 illuminates the volcanic arc, which appears as a segmented structure derived from the complex process of subduction of the Nazca and Caribbean plates under the South America Continent. The attenuation measurements are transformed into thermal measurement using standard rock physics relationships, supported by thermal estimations and geothermal gradient observations measured in wells. Active and inactive magmatic belts are associated with a range of relatively low temperatures (∼640 to ∼810 • C in the depth range of 25-100 km), which may be a consequence of the fluid content in hydrous minerals. Along the volcanic arc, the isotherms become shallower from South to North and are interrupted by a cold structure; this structure may reflect a lateral change of the mantle viscosity that prevents the continuity of the volcanic arc. Our estimations show an irregular depth-geometry of the isotherms, probably associated with recent slip events that have perturbed the thermal state along the study area. The isotherms also deepen to the West, probably due to the subduction process of the Nazca Plate (∼0-5 • N). In some areas, the isotherms follow a trend similar to that of a thrust fault-related folding geometry, which suggests a recent process of regional perturbation. We hypothesize that the Panama Arc collision at the north and the effect that imprint the Carnegie Ridge against the continent at the South are responsible for these thermal effects. The northern anomaly suggests thickening of the lithospheric system that prevents the development of the volcanic arc at the north of the Caldas Tear.

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Space‐weighted seismic attenuation mapping of the aseismic source of Campi Flegrei 1983–1984 unrest

Cited by 58 publications

References 42 publications

Complex Dome Growth at Campi Flegrei Caldera (Italy) in the Last 15 ka

Complex Dome Growth at Campi Flegrei Caldera (Italy) in the Last 15 ka

Anatomy of the Campi Flegrei caldera using Enhanced Seismic Tomography Models

Estimation of the Thermal Structure Beneath the Volcanic Arc of the Northern Andes by Coda Wave Attenuation Tomography

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