scholarly journals Some Investigations on a Possible Relationship between Ground Deformation and Seismic Activity at Campi Flegrei and Ischia Volcanic Areas (Southern Italy)

Geosciences ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 222 ◽  
Author(s):  
Ciro Ricco ◽  
Simona Petrosino ◽  
Ida Aquino ◽  
Carlo Del Gaudio ◽  
Mariarosaria Falanga
Keyword(s):  
Seismic Activity ◽  
Ground Deformation ◽  
Earth Tides ◽  
Quality Data ◽  
Campi Flegrei ◽  
Joint Analysis ◽  
Time Interval ◽  
Ground Tilt ◽  
Tectonic Earthquakes ◽  
Solid Earth Tides

In the present paper, we analyse ground tilt and seismicity at Campi Flegrei caldera and Ischia Island, two volcanic areas located in the south of Italy. These areas have been well studied for many years from a petrological, volcanological and geophysical view point. Moreover, due to the high seismic and volcanic risk for the populations living there, they are continuously monitored by networks of geophysical and geochemical sensors. We summarize the most important results that we obtained so far, concerning the observations of relationships between seismic activity and ground tilt anomalies, focusing on the time interval 2015–2018. First, we present a detailed description of the tiltmeter and seismic networks in both the investigated areas, as well as their development and improvement over time that has enabled high quality data collection. From the joint analysis of the seismic and borehole tiltmeter signals, we often notice concurrence between tilt pattern variations and the occurrence of seismicity. Moreover, the major tilt anomalies appear to be linked with the rate and energy of volcano-tectonic earthquakes, as well as with exogenous phenomena like solid Earth tides and hydrological cycles. The analysis that we present has potential applicability to other volcanic systems. Our findings show how the joint use tilt and seismic data can contribute to better understanding of the dynamics of volcanoes.

scholarly journals Short-term tidal variations in UT1: compliance between modelling and observation

2009 ◽  
Vol 5 (H15) ◽  
pp. 215-215 ◽  
Author(s):  
Sigrid Englich ◽  
Harald Schuh ◽  
Robert Weber
Keyword(s):  
Solid Earth ◽  
Earth Tides ◽  
Time Interval ◽  
Observation Data ◽  
Length Of Day ◽  
Tidal Effects ◽  
Short Term ◽  
Solid Earth Tides ◽  
Oceanic Tides ◽  
Tidal Variations

AbstractThe Earth rotation rate and consequently universal time (UT1) and length of day (LOD) are periodically affected by solid Earth tides and oceanic tides. Solid Earth tides induce changes with periods from around 5 days to 18.6 years, with the largest amplitudes occurring at fortnightly, monthly, semi-annual and annual periods, and at 18.6 years. The principal variations caused by oceanic tides have diurnal and semi-diurnal periods. For the investigation of the tidal effects with periods of up to 35 days, UT1 series are estimated from VLBI observation data of the time interval 1984–2008. The amplitudes and phases of the terms of interest are calculated and the results for diurnal and sub-diurnal periods are compared and evaluated with tidal variations derived from a GNSS-based LOD time series of 8 months. The observed tidal signals are finally compared to the predicted tidal variations according to recent geophysical models.

scholarly journals Modulation of Ground Deformation and Earthquakes by Rainfall at Vesuvius and Campi Flegrei (Italy)

2021 ◽  
Vol 9 ◽  
Author(s):  
Simona Petrosino ◽  
Ciro Ricco ◽  
Ida Aquino
Keyword(s):  
Diffusion Processes ◽  
Ground Deformation ◽  
Seasonal Pattern ◽  
Campi Flegrei ◽  
Volcanic System ◽  
Ground Tilt ◽  
Seismicity Rates ◽  
Fractured Medium ◽  
Hydrological Cycles ◽  
Underlying Mechanisms

Volcanoes are complex systems whose dynamics is the result of the interplay between endogenous and exogenous processes. External forcing on volcanic activity by seasonal hydrological variations can influence the evolution of a volcanic system; yet the underlying mechanisms remain poorly understood. In the present study, we analyse ground tilt, seismicity rates and rainfall amount recorded over 6 years (2015–2021) at Vesuvius and Campi Flegrei, two volcanic areas located in the south of Italy. The results indicate that at both volcanoes the ground deformation reflects the seasonality of the hydrological cycles, whereas seismicity shows a seasonal pattern only at Campi Flegrei. A correlation analysis on shorter time scales (days) indicates that at Vesuvius rain and ground tilt are poorly correlated, whereas rain and earthquakes are almost uncorrelated. Instead, at Campi Flegrei precipitations can affect not only ground deformation but also earthquake rate, through the combined action of water loading and diffusion processes in a fractured medium, likely fostered by the interaction with the shallow hydrothermal fluids. Our observations indicate a different behavior between the two volcanic systems: at Vesuvius, rain-induced hydrological variations poorly affect the normal background activity. On the contrary, such variations play a role in modulating the dynamics of those metastable volcanoes with significant hydrothermal system experiencing unrest, like Campi Flegrei.

scholarly journals Statistics of seismicity to investigate the Campi Flegrei caldera unrest

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Tramelli ◽  
C. Godano ◽  
P. Ricciolino ◽  
F. Giudicepietro ◽  
S. Caliro ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Central Area ◽  
Seismic Energy ◽  
Progressive Increase ◽  
Campi Flegrei ◽  
Cumulative Number ◽  
Seismic Parameters ◽  
Seismicity Rate ◽  
Seismic Catalogue ◽  
Vertical Ground

AbstractThe knowledge of the dynamic of the Campi Flegrei calderic system is a primary goal to mitigate the volcanic risk in one of the most densely populated volcanic areas in the world. From 1950 to 1990 Campi Flegrei suffered three bradyseismic crises with a total uplift of 4.3 m. After 20 years of subsidence, the uplift started again in 2005 accompained by a low increment of the seismicity rate. In 2012 an increment in the seismic energy release and a variation in the gas composition of the fumaroles of Solfatara (in the central area of the caldera) were recorded. Since then, a slow and progressive increase in phenomena continued until today. We analyze the INGV - Osservatorio Vesuviano seismic catalogue of Campi Flegrei from 2000 to 2020 in order to look for any variation in the seismic parameters and compare them with geochemical monitored ones. A remarkable correlation between independent variables of earthquake cumulative number, CO/CO2 values and vertical ground deformation reveals a likely common origin. Moreover the correlation between all the variables here analysed enlightens that the same origin can cause the temporal behavior of all these variables. We interpret the seismological, geochemical and geodetic observable in terms of the injection of magmatic fluids into the hydrothermal system or its pressurization.

scholarly journals The permeability and elastic moduli of tuff from Campi Flegrei, Italy: implications for ground deformation modelling

Solid Earth ◽  
2014 ◽  
Vol 5 (1) ◽  
pp. 25-44 ◽  
Author(s):  
M. J. Heap ◽  
P. Baud ◽  
P. G. Meredith ◽  
S. Vinciguerra ◽  
T. Reuschlé
Keyword(s):  
Ultrasonic Wave ◽  
Elastic Moduli ◽  
Ground Deformation ◽  
Laboratory Data ◽  
Campi Flegrei ◽  
Pore Collapse ◽  
Campanian Ignimbrite ◽  
Wave Velocities ◽  
Neapolitan Yellow Tuff ◽  
Dynamic Elastic Moduli

Abstract. The accuracy of ground deformation modelling at active volcanoes is a principal requirement in volcanic hazard mitigation. However, the reliability of such models relies on the accuracy of the rock physical property (permeability and elastic moduli) input parameters. Unfortunately, laboratory-derived values on representative rocks are usually rare. To this end we have performed a systematic laboratory study on the influence of pressure and temperature on the permeability and elastic moduli of samples from the two most widespread lithified pyroclastic deposits at the Campi Flegrei volcanic district, Italy. Our data show that the water permeability of Neapolitan Yellow Tuff and a tuff from the Campanian Ignimbrite differ by about 1.5 orders of magnitude. As pressure (depth) increases beyond the critical point for inelastic pore collapse (at an effective pressure of 10–15 MPa, or a depth of about 750 m), permeability and porosity decrease significantly, and ultrasonic wave velocities and dynamic elastic moduli increase significantly. Increasing the thermal stressing temperature increases the permeability and decreases the ultrasonic wave velocities and dynamic elastic moduli of the Neapolitan Yellow Tuff; whereas the tuff from the Campanian Ignimbrite remains unaffected. This difference is due to the presence of thermally unstable zeolites within the Neapolitan Yellow Tuff. For both rocks we also find, under the same pressure conditions, that the dynamic (calculated from ultrasonic wave velocities) and static (calculated from triaxial stress-strain data) elastic moduli differ significantly. The choice of elastic moduli in ground deformation modelling is therefore an important consideration. While we urge that these new laboratory data should be considered in routine ground deformation modelling, we highlight the challenges for ground deformation modelling based on the heterogeneous nature (vertically and laterally) of the rocks that comprise the caldera at Campi Flegrei.

scholarly journals Multiscale Analysis of DInSAR Measurements for Multi-Source Investigation at Uturuncu Volcano (Bolivia)

2019 ◽  
Vol 11 (6) ◽  
pp. 703 ◽  
Author(s):  
Andrea Barone ◽  
Maurizio Fedi ◽  
Pietro Tizzani ◽  
Raffaele Castaldo
Keyword(s):  
Multiscale Analysis ◽  
Cross Correlation ◽  
Ground Deformation ◽  
Vertical Component ◽  
Central Zone ◽  
Time Interval ◽  
Volcanic Complex ◽  
Magma Body ◽  
Deep Source ◽  
Good Agreement

Uturuncu volcano (southwestern Bolivia) is localized within one of the largest updoming volcanic zones, the Altiplano Puna Volcanic Complex (APVC). In several geodetic studies the observed uplift phenomenon is analyzed and modeled by considering a deep source, related to the Altiplano Puna Magma Body (APMB). In this framework, we perform a multiscale analysis on the 2003–2010 ENVISAT satellite data to investigate the existence of a multi-source scenario for this region. The proposed analysis is based on Cross-correlation and Multiridge method, pointing out the spatial and temporal multiscale properties of the deformation field. In particular, we analyze the vertical component of ground deformation during two time interval: within the 2005–2008 time interval an inflating source at 18.7 km depth beneath the central zone of the APVC is retrieved; this result is in good agreement with those proposed by several authors for the APMB. Between August 2006 and February 2007, we identify a further inflating source at 4.5 km depth, beneath Uturuncu volcano; the existence of this latter, located just below the 2009–2010 seismic swarm, is supported by petrological, geochemical, and geophysical evidence, indicating as a possible interpretative scenario the action of shallow, temporarily trapped fluids.

scholarly journals On the Influence of Diurnal and Subdiurnal Signals in the Normal Vector on Large Ring Laser Gyroscope Observations

2020 ◽  
Vol 177 (9) ◽  
pp. 4217-4228
Author(s):  
Monika Tercjak ◽  
André Gebauer ◽  
Marcin Rajner ◽  
Aleksander Brzeziński ◽  
Karl Ulrich Schreiber
Keyword(s):  
Solid Earth ◽  
Ring Laser ◽  
Earth Tides ◽  
Love Numbers ◽  
Ring Laser Gyroscope ◽  
Solid Earth Tides ◽  
Ocean Tidal Loading ◽  
Tidal Loading ◽  
Laser Gyroscope ◽  
The Impact

Abstract The ring laser gyroscope (RLG) technique has been investigated for over 20 years as a potential complement to space geodetic techniques in measuring Earth rotation. However, RLGs are also sensitive to changes in their terrestrial orientation. Therefore in this paper, we review how the high-frequency band (i.e. signals shorter than 0.5 cycle per day) of the known phenomena causing site deformation contribute to the RLG observable, the Sagnac frequency. We study the impact of solid Earth tides, ocean tidal loading and non-tidal loading phenomena (atmospheric pressure loading and continental hydrosphere loading). Also, we evaluate the differences between available models of the phenomena and the importance of the Love numbers used in modeling the impact of solid Earth tides. Finally, we compare modeled variations in the instrument orientation with the ones observed with a tiltmeter. Our results prove that at the present accuracy of the RLG technique, solid Earth tides and ocean tidal loading effects have significant effect on RLG measurements, and continental hydrosphere loading can be actually neglected. Regarding the atmospheric loading model, its application might introduce some undesired signals. We also show that discrepancies arising from the use of different models can be neglected, and there is almost no impact arising from the use of different Love numbers. Finally, we discuss differences between data reduced with tiltmeter observations and these reduced with modeled signal, and potential causes of this discrepancies.

scholarly journals On Investigations of the Tidal Waves Mf and Mm

1979 ◽  
Vol 82 ◽  
pp. 315-316
Author(s):  
G. P. Pil'nik
Keyword(s):  
Solid Earth ◽  
Elastic Properties ◽  
Earth Tides ◽  
Love Number ◽  
Astronomical Observations ◽  
Tidal Waves ◽  
The Earth ◽  
Astronomical Time ◽  
Solid Earth Tides

The comparison of astronomical time observations with the theory of solid-Earth tides makes it possible to determine the Love number, k, which characterizes the elastic properties of the Earth. In addition, the comparison of values of k determined from different tidal waves allows us to judge the accuracy of the nutational theory in astronomical observations since both tides and the Earth's nutation are produced by the same causes.

scholarly journals Granger Causality Analysis of Geophysical, Geodetic and Geochemical Observations during Volcanic Unrest: A Case Study in the Campi Flegrei Caldera (Italy)

Geosciences ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 185
Author(s):  
Simona Tripaldi ◽  
Sergio Scippacercola ◽  
Annarita Mangiacapra ◽  
Zaccaria Petrillo
Keyword(s):  
Granger Causality ◽  
Ground Deformation ◽  
Campi Flegrei ◽  
Test Results ◽  
Time Data ◽  
Causality Test ◽  
Campi Flegrei Caldera ◽  
System Pressure ◽  
Deformation Velocity ◽  
Granger Test

The recent signs of reawakening at Campi Flegrei caldera (Southern Italy) received a great deal of attention due to the issues related to the volcanic risk management in a densely populated area. This paper explores relations between ground deformations, seismicity and geochemical time series in the time span 2004–2016. The aim is to unravel primary processes of unrest and the related indicators which may change in time. Data structure and interactions among variables were examined applying the clustering analysis, the correlations and the Granger causality test. The hierarchical agglomerative clustering detected two sub-periods which were further investigated. In both sub-period causal links were observed between variables while correlations did not appear and vice versa. Thus, well established formal approaches are required to study causal relations. Granger test results indicate that during 2004–2011 the awakening unrest could be mainly ascribed to hydrothermal system pressure fluctuations, probably induced by deep-rooted fluids injection, and that ground deformation together with CO2/H2O appears the most suitable geo-indicators. The 2011–2016 sub-period is characterized by enhanced dynamical connectivity. Granger test results suggest that the unrest is driven by a more localized and shallower thermohydromechanical engine. CO/CO2, He/CH4 and ground deformation velocity are mutually interacting appearing the most suitable geo-indicators.

scholarly journals Ground deformation at calderas driven by fluid injection: modelling unrest episodes at Campi Flegrei (Italy)

2011 ◽  
Vol 187 (2) ◽  
pp. 833-847 ◽  
Author(s):  
A. Troiano ◽  
M.G. Di Giuseppe ◽  
Z. Petrillo ◽  
C. Troise ◽  
G. De Natale
Keyword(s):  
Ground Deformation ◽  
Campi Flegrei ◽  
Fluid Injection
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