scholarly journals A new method to assess long‐term sea‐bottom vertical displacement in shallow water using a bottom pressure sensor: Application to Campi Flegrei, Southern Italy

2016 ◽  
Vol 121 (11) ◽  
pp. 7775-7789 ◽  
Author(s):  
Francesco Chierici ◽  
Giovanni Iannaccone ◽  
Luca Pignagnoli ◽  
Sergio Guardato ◽  
Marina Locritani ◽  
...  
Keyword(s):  
Shallow Water ◽  
Pressure Sensor ◽  
Southern Italy ◽  
Vertical Displacement ◽  
New Method ◽  
Campi Flegrei ◽  
Bottom Pressure ◽  
Sensor Application ◽  
Sea Bottom

scholarly journals Aseismic strain episodes at Campi Flegrei Caldera, Italy

2021 ◽  
Vol 52 ◽  
pp. 119-129
Author(s):  
Bellina Di Lieto ◽  
Pierdomenico Romano ◽  
Roger Bilham ◽  
Roberto Scarpa
Keyword(s):  
Surface Deformation ◽  
Vertical Displacement ◽  
Campi Flegrei ◽  
Gas Emission ◽  
Campi Flegrei Caldera ◽  
Transient Strain ◽  
Long Baseline ◽  
Emission Activity ◽  
Microseismic Activity

Abstract. Since 2004 a research project has been developed to monitor subsurface deformation of Italian volcanoes using borehole strainmeters and long-baseline tiltmeters. Six Sacks-Evertson dilatometers were installed around Campi Flegrei caldera and Vesuvius during 2004–2005 (Scarpa et al., 2007), and in 2008 these instruments were supplemented by two arrays of 28–280 m long water-tube tiltmeters in underground tunnels. Relevant strainmeter and tiltmeter data have been collected and analysed from the instruments installed near Campi Flegrei caldera during the recent unrest episodes. In the period 2004–2005 strain, tilt and GPS data from Campi Flegrei indicate the onset of surface deformation that accompanied a low rate of vertical displacement that continued to 2006, corresponding to an increase of CO2 emission. This strain episode preceded caldera microseismic activity by a few months, as was observed also during a significant inflation episode in 1982. Other transient strain episodes occurred in October 2006, which were accompanied by a swarm of VT (Volcano-Tectonic) and LP (Long Period) events, in 2009, at the time of renewed gas emission activity at Solfatara, and again in March 2010, several minutes before a seismic swarm. The time scale of these transient strain events ranges from some hours to several days, putting tight constraints on the origin of ground uplifts at Campi Flegrei. Their location is compatible with a source inferred from long term deformation signals, located about 4 km beneath Pozzuoli. A proposed mechanism for these aseismic strain episodes is that they are associated with magma growth in reservoirs with occasional pressure relief associated with the leakage of gas.

Doming and faulting processes driving ground deformation at Campi Flegrei caldera (southern Italy): a modeling for the last 6 ka

2020 ◽  
Author(s):  
Stefano Vitale ◽  
Roberto Isaia ◽  
Jacopo Natale ◽  
Francesco D'Assisi Tramparulo
Keyword(s):  
Southern Italy ◽  
Ground Deformation ◽  
Vertical Displacement ◽  
Time Frame ◽  
Plinian Eruption ◽  
Tectonic Activity ◽  
Campi Flegrei ◽  
Deformation Pattern ◽  
Campi Flegrei Caldera ◽  
Caldera Floor

<p>We investigated the major episodes of dome growth in the Campi Flegrei caldera occurred during the last period of large eruptive activity (Epoch 3, between 5.5 and 3.5 ka), and in the historical time. The first doming event occurred at the start of Epoch 3  where the caldera floor raised for at least 100 m. Following the Plinian eruption of Agnano-Monte Spina (AMS, 4.55 ka), a new uplift phase occurred with the set up of several lava domes (e.g., Olibano, Accademia and Solfatara cryptodome), the Averno-Solfatara  (AVS, 4.3 ka) and Astroni (AST, 4.2 ka) eruptions. This unrest episode was accompanied by severe and widespread faulting and fracturing well recorded in the stratigraphic record (Vitale et al., 2019). Finally, the last episodes of doming occurred before the eruption of Monte Nuovo volcano (MN, 1538 CE) and in the last century (1950-1985 CE). The 1538 CE uplift reached a maximum vertical displacement of ca. 15 m, whereas the 1950-1985 events reached a total dislocation of ca. 4 m. In order to study the former ground deformation pattern, we reconstructed the top surface of the La Starza succession, the latter formed by marine-transitional sediments deposited between 15 and 5.5 ka deposited in large part of the caldera floor. We used information from onland well-logs and seismic profiles in the Gulf of Pozzuoli. The same approach was used for the top surface of the younger marine succession, called Pozzuoli Unit (PU) (Isaia et al., 2019), emplaced following the AMS eruption and predating the AVS eruption. Subtracting the historical deformation pattern and considering the sea-level change in that time frame, we observe that the center of vertical deformation was located, for both Top Starza and Top PU surfaces, close to the Cigliano vent, and therefore not coinciding with the 1538 CE and recent deformation center, both defined by the same deformation center located close to the town of Pozzuoli. The resulting surfaces well mark local deformations related to the activity of major faults and the minor caldera formed following the AMS Plinian eruption. The restoring of the deformation of major faults with the Okada’s fault model has furnished useful information about the amount of displacement and rates of the faults' activity in the last ca. 6 ka.</p><p>Isaia, R., Vitale, S., Marturano, A., Aiello, G., Barra, D., Ciarcia, S., Iannuzzi, E., Tramparulo, F.D.A., 2019. High-resolution geological investigations to reconstruct the long-term ground movements in the last 15 kyr at Campi Flegrei caldera (southern Italy). Journal of Volcanology and Geothermal Research, 385, 143-158. doi: 10.1016/j.jvolgeores.2019.07.012</p><p>Vitale, S., Isaia, R., Ciarcia, S., Di Giuseppe, M. G., Iannuzzi, E., Prinzi, E. P., Tramparulo, F.D’A., Troiano, A. 2019. Seismically induced soft‐sediment deformation phenomena during the volcano‐tectonic activity of Campi Flegrei caldera (southern Italy) in the last 15 kyr. Tectonics, 38(6), 1999-2018.</p>

scholarly journals Novel robust time series analysis for long-term and short-term prediction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroshi Okamura ◽  
Yutaka Osada ◽  
Shota Nishijima ◽  
Shinto Eguchi
Keyword(s):  
Robust Regression ◽  
Simulated Data ◽  
New Method ◽  
Short Term ◽  
Least Absolute Deviations ◽  
Term Prediction ◽  
Regression Approach ◽  
Short Term Prediction ◽  
Long Term Prediction

AbstractNonlinear phenomena are universal in ecology. However, their inference and prediction are generally difficult because of autocorrelation and outliers. A traditional least squares method for parameter estimation is capable of improving short-term prediction by estimating autocorrelation, whereas it has weakness to outliers and consequently worse long-term prediction. In contrast, a traditional robust regression approach, such as the least absolute deviations method, alleviates the influence of outliers and has potentially better long-term prediction, whereas it makes accurately estimating autocorrelation difficult and possibly leads to worse short-term prediction. We propose a new robust regression approach that estimates autocorrelation accurately and reduces the influence of outliers. We then compare the new method with the conventional least squares and least absolute deviations methods by using simulated data and real ecological data. Simulations and analysis of real data demonstrate that the new method generally has better long-term and short-term prediction ability for nonlinear estimation problems using spawner–recruitment data. The new method provides nearly unbiased autocorrelation even for highly contaminated simulated data with extreme outliers, whereas other methods fail to estimate autocorrelation accurately.

scholarly journals Energy–Vorticity Theory of Ideal Fluid Mechanics

2009 ◽  
Vol 66 (7) ◽  
pp. 2073-2084 ◽  
Author(s):  
Peter Névir ◽  
Matthias Sommer
Keyword(s):  
Fluid Mechanics ◽  
Shallow Water ◽  
Ideal Fluid ◽  
Characteristic Property ◽  
Incompressible Flows ◽  
Climate Simulations ◽  
Shallow Water Models ◽  
Complete Analogy ◽  
Potential Enstrophy

Abstract Nambu field theory, originated by Névir and Blender for incompressible flows, is generalized to establish a unified energy–vorticity theory of ideal fluid mechanics. Using this approach, the degeneracy of the corresponding noncanonical Poisson bracket—a characteristic property of Hamiltonian fluid mechanics—can be replaced by a nondegenerate bracket. An energy–vorticity representation of the quasigeostrophic theory and of multilayer shallow-water models is given, highlighting the fact that potential enstrophy is just as important as energy. The energy–vorticity representation of the hydrostatic adiabatic system on isentropic surfaces can be written in complete analogy to the shallow-water equations using vorticity, divergence, and pseudodensity as prognostic variables. Furthermore, it is shown that the Eulerian equation of motion, the continuity equation, and the first law of thermodynamics, which describe the nonlinear evolution of a 3D compressible, adiabatic, and nonhydrostatic fluid, can be written in Nambu representation. Here, trilinear energy–helicity, energy–mass, and energy–entropy brackets are introduced. In this model the global conservation of Ertel’s potential enstrophy can be interpreted as a super-Casimir functional in phase space. In conclusion, it is argued that on the basis of the energy–vorticity theory of ideal fluid mechanics, new numerical schemes can be constructed, which might be of importance for modeling coherent structures in long-term integrations and climate simulations.

A Low-Range Drift-Free Bio-compatible Pressure Sensor Based on P(VDF-TrFE) Piezoelectric Thin Film

2009 ◽  
Vol 1222 ◽  
Author(s):  
Xiaoyang Li ◽  
Timothy Reissman ◽  
Fan Yu ◽  
Edwin C. Kan
Keyword(s):  
Thin Film ◽  
Blood Pressure ◽  
Pressure Sensor ◽  
Equivalent Circuit Model ◽  
Swelling Pressure ◽  
Pressure Monitoring ◽  
Sensing Element ◽  
Piezoelectric Resonance ◽  
Piezoelectric Thin Film

AbstractA low-range pressure sensor (0-100kPa) based on the P(VDF-TrFE) piezoelectric thin film is proposed, where the long-term drift is eliminated by operating near the piezoelectric resonance. The pressure sensor is designed for blood pressure and tissue swelling pressure monitoring. The poled 50μm±1μm P(VDF-TrFE) copolymer film is used as the sensing element, with all fabrication and assembly materials biocompatible. A modified Butterworth-Van Dyke (BVD) [1] equivalent circuit model is used to characterize the sensor behavior. The pressure sensor exhibits negligible drift in weeks of operation. The device shows a sensitivity of 0.038MHz/kPa resonance frequency shift under stress, which leads to a maximum readout change of 1.1%/kPa in the present setup.

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