The 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/CO
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.
The inter-arrival times of the post 2000 seismicity at Campi Flegrei caldera are statistically distributed into different populations. The low inter-arrival times population represents swarm events, ...while the high inter-arrival times population marks background seismicity. Here, we show that the background seismicity is increasing at the same rate of (1) the ground uplift and (2) the concentration of the fumarolic gas specie more sensitive to temperature. The seismic temporal increase is strongly correlated with the results of recent simulations, modelling injection of magmatic fluids in the Campi Flegrei hydrothermal system. These concurrent variations point to a unique process of temperature-pressure increase of the hydrothermal system controlling geophysical and geochemical signals at the caldera. Our results thus show that the occurrence of background seismicity is an excellent parameter to monitor the current unrest of the caldera.
We have analyzed a multiparametric data set of seismological, geodetic and geochemical data recorded at Campi Flegrei caldera since 1982. We focus here on the period 1989–2010 that followed the last ...bradyseismic crisis of 1982–1984. Since then, there have been at least five repeated minor episodes of ground uplift accompanied by seismicity. We have reanalyzed old paper and digital seismic data sets dating back to 1982. The paper recordings show evidence of long‐period events in January 1982 and March 1989, and we have digitized some of these significant waveforms. Furthermore, the revision of digital seismograms dating back to 1994 shows a significant swarm of long‐period events in August 1994. Volcano‐tectonic and long‐period events hypocenters have been relocated in a three‐dimensional velocity model. Statistical analysis of volcano‐tectonic seismicity shows many similarities and few differences between 1982–1984 and the following period 1989–2010. Long‐period waveforms have been analyzed using spectral analysis, which shows a grouping into three macrofamilies. Similarities in the seismic signature of episodes of minor uplift suggest that they originate from the injection of fluids into the deep part of a geothermal reservoir (about 2.5 km depth) and in its transfer toward a shallower part (about 0.75 km depth). Most of the observed geophysical signals are related to this second phase. The evidence consists of spatial and temporal connections between the ground deformation, long‐period and volcano‐tectonic seismicity and changes in the geochemical parameters of fumaroles. In this study we focused our analysis on two uplift episodes observed in 2000 and 2006. The joint inversion of Differential Synthetic Aperture Radar (DInSAR) and tiltmeter data show that during these periods the ground deformation was generated by at least two distinct sources located at different depths, with the shallower activated in the later stages of the uplift episodes. Our interpretation of the recent dynamics of Campi Flegrei is that the deep part of the geothermal reservoir inflates in response to mass and heat input from a magmatic source. When the pressure exceeds a threshold, fluids starts to migrate into the shallower part. During this transfer, long‐period sources are activated in response to the fluid motion. The gradual diffusion of fluids in the surrounding rocks lowers the resistance of a pervasive fracture system generating shallow microseismicity. Finally, fluids reach the surface, which gives a distinct geochemical signature to the overlying fumaroles.
Key Points
Campi Flegrei geothermal system is composed of at least two parts
Fluid flow in the geothermal system is the main source of seismicity
Geochemical and geophysical signals correlate in a common framework
Within a general volcanic unrest in the densely urbanized area of Campi Flegrei caldera (Italy) an increase in the activity of Pisciarelli hydrothermal area is occurring. The seismic amplitude of ...Pisciarelli fumarolic tremor is a proxy for the fluid emission rate of the entire Solfatara‐Pisciarelli hydrothermal system. The long‐term analysis indicates a significant increase, by a factor of ~3 of the fumarolic tremor amplitude since May 2017. This increment matches with the trend of geochemical and seismic parameters observed in Campi Flegrei, therefore highlighting that Pisciarelli is a key site to monitor the volcanic unrest underway in this high‐risk caldera. The analysis of data from three closely spaced seismic stations provided new clues about the source mechanism of the tremor. Analyzing the fumarolic tremor amplitude we could also identify an episode of enlargement of the emission area close to the main fumarole of Pisciarelli. We propose a monitoring system based on the fumarolic tremor analysis, which provides real‐time information on the Pisciarelli hydrothermal activity and therefore on the current unrest in Campi Flegrei caldera.
Key Points
Fumarolic tremor indicates a new increase of the Pisciarelli hydrothermal activity linked to the current large‐scale unrest at Campi Flegrei
The fumarolic tremor analysis allowed us to identify an episode of enlargement of Pisciarelli mud emissions
We propose a method for monitoring the hydrothermal system based on proximal measurements of fumarolic tremor
Fluids supplied by stored magma at depth are causal factors of volcanic unrest, as they can cause pressurization/heating of hydrothermal systems. However, evidence for links between hydrothermal ...pressurization, CO2 emission and volcano seismicity have remained elusive. Here, we use recent (2010−2020) observations at Campi Flegrei caldera (CFc) to show hydrothermal pressure, gas emission and seismicity at CFc share common source areas and well-matching temporal evolutions. We interpret the recent escalation in seismicity and surface gas emissions as caused by pressure-temperature increase at the top of a vertically elongated (0.3–2 km deep) gas front. Using mass (steam) balance considerations, we show hydrothermal pressurization is causing energy transfer from the fluids to the host rocks, ultimately triggering low magnitude earthquakes within a seismogenetic volume containing the hydrothermal system. This mechanism is probably common to other worldwide calderas in similar hydrothermal activity state.
•Gas-geoindicators indicate an escalation of the hydrothermal P-T Campi Flegrei•Pressurization causes increase of the CO2 emission at Solfatara (up to 5000 t/d)•Increasing hydrothermal P-T and CO2 emission trigger low magnitude earthquakes
Campi Flegrei caldera (Southern Italy) is one of the most hazardous volcanic complexes in the world since it is located inside the densely inhabited urban district of Naples-Pozzuoli. In the past, ...the caldera has produced devastating to moderate eruptions and periodically undergoes from strong to minor uplift episodes, named “bradyseism”, almost always accompanied by seismic swarms. Starting from 2005 Campi Flegrei has undergone an unrest crisis, characterized by ground uplift, localized gas emissions and seismicity, often occurring in seismic swarms. As a consequence, the monitoring activities have been progressively increasing, producing a huge amount of data, difficult to manage and match. GIS (Geographical Information System) represents a potent tool to manage great quantity of data, coming from different disciplines. In this study, we show two GIS technology applications to the seismic catalogue of Campi Flegrei. In the first one, a high-quality dataset is extracted from the GeoDatabase addressed to seismological studies that require high precision earthquake locations. In the second application, GIS are used to extract, visualize and analyse the typical seismic swarms of Campi Flegrei. Moreover, density and seismic moment distribution maps were generated for these swarms. In the last application, the GIS allow to highlight a clear variation in the temporal trend of the seismic swarms at Campi Flegrei.
This paper describes the characteristics of the seismicity in the volcanic Neapolitan area during the year 2000 recorded by the monitoring seismic network of the Osservatorio Vesuviano. In ...particular, a detailed analysis of the seismicity of Vesuvius is presented. We compared the seismic velocity models available for the Vesuvius area locating the earthquakes recorded in the year 2000 and on the basis of the results, we introduce for routine earthquake location the new velocity model obtained by the seismic tomography experiments (TomoVes) performed in the area. We also determined the focal mechanisms and analysed the seismicity rate, comparing the results with those obtained for the past years. After the introduction of the new acquisition system at the Osservatorio Vesuviano, a re-calibration of the duration magnitude scale was necessary to avoid biases related to the different instrumental response. Consequently, we re-calibrated the magnitude relation used for the Vesuvius earthquakes, obtaining a new formula to be used for the earthquakes recorded by the new acquisition system. Finally, we give a description of the seismic activity in the Campi Flegrei area during the summer of 2000.
Intussusception is a common condition of bowel obstruction in pediatric patients. However, 5% of all cases occur in adults, mostly aged over fifty, with no difference based on sex, representing about ...1% of all causes of bowel obstruction. Compared to pediatric population, it is triggered by a pathologic lead point in about 85% of cases, represented in 60% of cases by malignant and benign neoplasms. Among these neoplasms, an inflammatory fibroid polyp (IFP), a benign neoplastic submucosal lesion also known as Vanek's tumor, is considered a very uncommon cause of adult intussusception. Clinical presentation could differ by location and size of tumor, and may include abdominal pain, nausea, vomiting, diarrhea or constipation, bleeding, weight loss, palpable abdominal mass, bowel obstruction, and gastrointestinal bleeding. Considering its common and non-specific symptoms, radiologic imaging plays a key role in the diagnosis of an IFP, especially computed tomography (CT) scan, which represents the most sensitive modality to confirm intussusception. However, bowel sonography (BS) has become an accurate procedure in various pathological intestinal diseases, also including intussusception. In this paper, we report a rare case of ileo-ileal intussusception secondary to Vanek's tumor diagnosed by BS.
Abstract
Background
The diagnosis of small bowel Crohn’s disease (CD) is mainly performed by ileo-colonoscopy (IC), while the assessment of its extension can be achieved non-invasively by using ...magnetic resonance enterography (MRE) and bowel sonography (BS) in view of a very concordant agreement about diagnostic accuracy. More recently, hand-held sonography has been used effectively in cardiological and orthopaedical diagnostic settings, while data about its use for CD diagnosis are still scarce. The aim of this pilot study was to evaluate the diagnostic accuracy of hand-held BS (HHBS) in comparison with MRE for the diagnosis of CD.
Methods
From September 2019 to June 2021, we prospectively studied 85 consecutive subjects who attended our third level IBD Unit for suspected CD. All patients underwent IC (as gold standard for CD diagnosis), HHBS (VScan, dual probe, 5–7.5 MHz; General Elelectric®) and MRE in a random order and blind way. MRE was assumed as reference standard for defining the extension of small bowel CD. Bivariate correlation about CD extension between MRE and HHBS was calculated by Spearman’s coefficient (r). To test the consistency between MRE and HHBS for CD location and complications (strictures, abscesses, fistulas) the Cohen’s k measure was applied. A p value of 0.05 was considered significant.
Results
The diagnosis of small bowel CD was made in 48 out of 85 subjects (56%), whereas the remaining 37 subjects received a different diagnosis. Sensitivity, specificity, positive and negative predictive values for CD diagnosis were 87% (95%CI 74–95%), 91% (95%CI 78–98%), 91% (95%CI 78–96%), 88% (95%CI 77–93%) for HHBS (TP 42, TN 34, FP 3, FN 6) and 92% (95%CI 80–97%), 95% (95%CI 81–99%), 94% (95%CI 81–98%), 91% (95%CI 85–97%) for MRE (TP 44, TN 35, FP 2, FN 4), without significant differences (p=N.S.). On the other hand, MRE was superior to HHBS in defining CD extension (r=0.67; p<0.01) and location (k = 0.81; p<0.01). Also, MRE showed a better diagnostic performance than HHBS for detecting strictures (k=0.75; p<0.01), abscesses (k=0.68; p<0.01) and fistulas (k=0.65; p<0.01).
Conclusion
HHBS and MRE are two accurate and non-invasive procedures for the diagnosis of CD, even if MRE appears to be more sensitive in defining the extension, location and intestinal complications. HHBS could be used as effective ambulatory (or out-of-office) screening tool for selecting the patients to submit to MRE examination because of high probability of CD diagnosis.
Sclerosing mesenteritis (SM) is an idiopathic disorder affecting mesentery, characterized by fat necrosis, chronic inflammation and fibrosis. The clinical presentation varies from asymptomatic cases ...to acute abdomen. The diagnosis is suggested by imaging but can be definitely established only by biopsies. In this paper, we discuss ultrasonography-based management of SM.
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