Papers by Giovanni Martinelli
Frontiers in Earth Science
The Holocene, 2019
Among natural hazards, mud volcanoes can damage property and infrastructures and affect hillslope... more Among natural hazards, mud volcanoes can damage property and infrastructures and affect hillslope evolution at different spatial and temporal scales. The results of 10-year-long multidisciplinary investigations performed on a Roman-age archaeological site, La Rovina di Montegibbio, are presented, showing a peculiar example of mutual interplay between human settlement and geological forcing in the mud-volcanic environment. The site (350 m a.s.l.) lies at the termination of the upper Secchia River catchment, near the town of Sassuolo (Modena Province). Here, a 4-km-long mud volcano belt borders the Apennines chain front, comprising one of the most prominent mud volcanoes of Italy ( Salsa di Montegibbio), and the still-active chain hinge tectonics gives origin to gas and oil seeps. Based on geological, geoarchaeological, palaeobotanical, geochemical, geophysical records and analytical data, we unravel the onset, the evolution and the abandonment of the settlement in relation to the exi...
Water
This study sums up the first estimates of the young water fraction (Fyw; here understood as the p... more This study sums up the first estimates of the young water fraction (Fyw; here understood as the percentage proportion of groundwater passing through the well’s screen and younger than approximately 2–3 months) from groundwater collected in 75 wells from alluvial fans facing the northern Italian Apennines of Italy. The Fyw estimates were based on a monthly dataset of water-stable isotopes (oxygen-18 (18O)) from surficial water (9 rivers), while the dataset of groundwater (75 wells) consisted of three-monthly isotopic data. In the cases of surficial water and stable isotopes, these lasted over the period of January 2003 to December 2007, while in the case of groundwater, the data were collected from January 2005 to December 2007. The values of Fyw were estimated by means of a sine-wave fitting technique; the results made evident the presence of unexpectedly reduced differences between groundwater. In particular, shallower groundwater hosted in aquifers from the apical parts of the all...
GNGTS 2009, Nov 16, 2009
A seguito del terremoto del 6 aprile sono state eseguite campagne di misure geochimiche con lo sc... more A seguito del terremoto del 6 aprile sono state eseguite campagne di misure geochimiche con lo scopo di verificare le modificazioni indotte dal terremoto, le relazioni fluidi/strutture tettoniche e l'origine dei fluidi (Italiano et al., 2001, 2004, 2005, 2007a, b, 2008, 2009a, b). Sono stati prelevati campioni di gas da pozzi ubicati in area epicentrale noti nella zona come “soffianti”, sono state eseguite misure di degassamento al suolo nelle aree interessate da fratturazione (indicazioni da Emergeo) e sono stati scaricati i dati di flusso di CO2 da ...
The Nirano Salse, known since the Roman Times, are one of the most beautiful and scenic mud volca... more The Nirano Salse, known since the Roman Times, are one of the most beautiful and scenic mud volcanoes areas of Italy with thousands of visitors every year. In this work, we apply hydrogeological techniques to characterize mud levels in the Salse by means of GPS-RTK positioning and continuous level logging within mud conduits. Our results suggest that different mud levels in mud volcanoes clusters are due to the different gas-liquid ratio in the conduits and not necessarily exclude interconnection at depth, a hypothesis, on the other hand, that seems strengthened by mud level time series correlations. The presence of shallow aquifers at a depth of 5 to 30 m is also supported by our field data. These shallow aquifers may provide a temporary storage for the ascending gas and when fluid pressure in these aquifers exceeds the tensional strength of the sedimentary rock, leakage of fluids to the surface would occur.
Bollettino di Geofisica Teorica ed Applicata
Hydrological and hydrogeochemical observations (piezometry, chemistry, electric properties, etc.)... more Hydrological and hydrogeochemical observations (piezometry, chemistry, electric properties, etc.) carried out in groundwaters in Italy in the past 40 years have been recovered and processed. Available data time series recorded by government agencies, scientific institutions and independent researchers in the field of groundwater and geochemical monitoring in 5480 different sites have been recovered, systematized and processed. Meteorological data useful for data evaluation have been recovered too. Some possible precursors have been identified but the relatively high amount of earthquakes not preceded by hydrologic or geochemical anomalies suggest the need to consider all together geophysical and geochemical parameters for future researches. Highest amount of data collected by manual sampling were found in the Lombardy, Veneto, and Emilia-Romagna regions, while most of automatically recorded data were found in the Tuscany region.
Chemical Geology, 2013
Several studies performed in the past 30 years suggested the existence of anomalous space-time tr... more Several studies performed in the past 30 years suggested the existence of anomalous space-time transients, in the thermal infrared (TIR) radiation emitted by the Earth, possibly related to earthquake preparatory phenomena. Among various theories about their origin, the abrupt increase in greenhouse gas (such as CO 2 , CH 4 , etc.) emission rates was also proposed to explain the appearance of anomalous TIR signal transients in some relation with the place and the time of earthquake occurrence. As, under stable atmospheric conditions, the accumulation/dispersion of gases in the air depends on their molecular weight, CO 2 tends to collect near the ground and layer forming "rivers" and/or "lakes" following terrain morphology close to its sources. On the contrary, the dispersion pattern of CH 4 , whose mass is smaller than that of CO 2 , is less affected by the terrain morphology so that the gas tends to be dispersed very readily, basically governed by the wind and normal atmospheric turbulence. If TIR anomalies are effectively related to exceptional degassing events, such differences should produce very different spatial/temporal patterns in the TIR anomalies observed, depending on the greenhouse gas emanated. In this paper, this hypothesis has been tested from different viewpoints and the results show that: a) an increase of only 2-3 times the normal CO 2 mixing ratio level is sufficient to justify the excesses observed in TIR signal. b) areas dominated by diffusing gases which are heavier than the air (like CO 2) show (as expected) anomalous TIR patterns which follow morphological lineaments (e.g. tectonic faults); in areas dominated by diffusing gases which are lighter than the air (like CH 4) the TIR patterns observed spread over wide zones, following prevailing winds and diffusing around with less marked correlation with morphological lineaments. c) anomalous TIR patterns were observed over the Azerbaijan region during the Bozdag-Guzdak mud volcano eruption (May 1995), showing exactly the same spatial/temporal behavior expected for methanedominated degassing areas.
Journal of Hydrology, 2014
ABSTRACT O-18/O-16, D/H, tritium and carbon isotopes were analysed together with the main geochem... more ABSTRACT O-18/O-16, D/H, tritium and carbon isotopes were analysed together with the main geochemical parameters of selected wells of groundwaters in the Emilia-Romagna region. The isotope data collected in a three-year monitoring program of surface waters allowed a subdivision of the studied region within the main feeding areas of the Po and Apennine Rivers. The isotopic investigation demonstrated the existence of palaeowaters hosted in deep aquifers in the plains and their overexploitation, which induced land subsidence phenomena. Groundwater stable isotopes have been utilized as a proxy for temperature and have shown significant atmospheric temperature variations over the past 30,000 years.
A hydrogeochemical prospection has been carried out in the Milano province with the purpose to be... more A hydrogeochemical prospection has been carried out in the Milano province with the purpose to better identify and characterize Nitrogen pollution sources. A network of 90 wells has been considered for geochemical prospection and 37 wells were also considered for isotopic survey. A geochemical stratification both in chemical characters and in isotopic ones has been identified and related to local pollution phenomena. The organic character of Nitrogen pollution phenomena has been identified and related to vulnerability characters of surveyed area. The obtained results allow to improve previous vulnerability mapping methods.
Water, 2022
This study sums up the first estimates of the young water fraction (Fyw; here understood as the p... more This study sums up the first estimates of the young water fraction (Fyw; here understood as the percentage proportion of groundwater passing through the well’s screen and younger than approximately 2–3 months) from groundwater collected in 75 wells from alluvial fans facing the northern Italian Apennines of Italy. The Fyw estimates were based on a monthly dataset of water-stable isotopes (oxygen-18 (18O)) from surficial water (9 rivers), while the dataset of groundwater (75 wells) consisted of three-monthly isotopic data. In the cases of surficial water and stable isotopes, these lasted over the period of January 2003 to December 2007, while in the case of groundwater, the data were collected from January 2005 to December 2007. The values of Fyw were estimated by means of a sine-wave fitting technique; the results made evident the presence of unexpectedly reduced differences between groundwater. In particular, shallower groundwater hosted in aquifers from the apical parts of the alluvial fans (i.e., aquifers characterized by the coarsest materials such as gravels and sands, and closest to the recharge areas) showed similar values of Fyw to the deepest aquifers from the distal parts; however, former studies mentioned here evidenced the existence of poorly recharged old groundwater. Our results seem to confirm a complex behavior of these aquifers compared with what had previously been thought.
Hydrological and hydrogeochemical observations (piezometry, chemistry, electric properties, etc.)... more Hydrological and hydrogeochemical observations (piezometry, chemistry, electric properties, etc.) carried out in groundwaters in Italy in the past 40 years have been recovered and processed. Available data time series recorded by government agencies, scientific institutions and independent researchers in the field of groundwater and geochemical monitoring in 5480 different sites have been recovered, systematized and processed. Meteorological data useful for data evaluation have been recovered too. Some possible precursors have been identified but the relatively high amount of earthquakes not preceded by hydrologic or geochemical anomalies suggest the need to consider all together geophysical and geochemical parameters for future researches. Highest amount of data collected by manual sampling were found in the Lombardy, Veneto, and Emilia-Romagna regions, while most of automatically recorded data were found in the Tuscany region.
Minerals
Seismic hazard reduction policies usually utilize earthquake catalogues and probability evaluatio... more Seismic hazard reduction policies usually utilize earthquake catalogues and probability evaluations of occurrence. Further geophysical and geochemical parameters could contribute to hazard reduction policies as is currently the case in some countries, such as Iceland, Taiwan, China and Russian Federation. In the past four decades, intense research activity carried out by many different institutions in Italy has allowed us to recognize the most relevant sensitive sites for detecting acceleration in crustal deformation processes by means of geofluids monitoring. All scientific papers published in the period 1976–2020 concerning tectonic-related signals in geofluids have been considered. An in-depth review of previous and present-day research activities, as well as an update of two unpublished time series recorded in Central and southern Italy, has contributed to identifying areas where an instrumental array is still lacking and the most relevant priority areas for monitoring activitie...
18O/16O, D/H, tritium and carbon isotopes were analysed together with the main geochemical parame... more 18O/16O, D/H, tritium and carbon isotopes were analysed together with the main geochemical parameters of selected wells of groundwaters in the Emilia-Romagna region. The isotope data collected in a threeyear monitoring program of surface waters allowed a subdivision of the studied region within the main feeding areas of the Po and Apennine Rivers. The isotopic investigation demonstrated the existence of palaeowaters hosted in deep aquifers in the plains and their overexploitation, which induced land subsidence phenomena. Groundwater stable isotopes have been utilized as a proxy for temperature and have shown significant atmospheric temperature variations over the past 30,000 years.
Water, 2020
Nowadays, climate changes and increased water demand for human and agricultural purposes pose imp... more Nowadays, climate changes and increased water demand for human and agricultural purposes pose important questions for the groundwater management of alluvial aquifers facing the northern Italian Apennines. The large groundwater withdrawals, coupled with an overall worsening of the water quality, requires a detailed knowledge of the recharge mechanisms of these aquifers that can be useful for further adaptation measures. Concerning the recharge area of the alluvial aquifers (i.e., apices made up of gravelly materials), the present study investigates a dataset made up of 282 water samples for which stable isotopes oxygen-18 (18 O) and deuterium (2 H) are available. The latter involves precipitations (three rain gauges), surface water (five rivers) and groundwater (twenty wells) from five selected alluvial fans. The study confirms that the different isotopic signatures characterizing rain and river water from this area can be exploited for preliminary characterization of their significa...
Geosciences
This paper presents the results of measurements performed on α-quartz subjected to shear stress i... more This paper presents the results of measurements performed on α-quartz subjected to shear stress in dry conditions, to understand the relationship between the shear intensity and the resulting physical and chemical effects. If a shear stress of intensity higher than 100 MPa is applied continuously to alpha quartz crystals, they will tend to lose their crystallinity, progressively reduce their friction coefficient (Cof) and change into a low-order material, apparently amorphous under X-ray diffraction, but with a structure different from silica glass. Raman and Pair Distribution Function analyses suggested a structure like cristobalite, a silica polymorph well-known for its auxetic behavior, i.e., having a negative Poisson ratio. This elastic parameter pre-eminently controls the friction coefficient of the material and, if it is negative, the Cof lowering. As a result, the increase in low crystallinity cristobalite is sufficientto explain the lowering of the quartz friction coefficien...
Water
Nowadays, climate changes and increased water demand for human and agricultural purposes pose imp... more Nowadays, climate changes and increased water demand for human and agricultural purposes pose important questions for the groundwater management of alluvial aquifers facing the northern Italian Apennines. The large groundwater withdrawals, coupled with an overall worsening of the water quality, requires a detailed knowledge of the recharge mechanisms of these aquifers that can be useful for further adaptation measures. Concerning the recharge area of the alluvial aquifers (i.e., apices made up of gravelly materials), the present study investigates a dataset made up of 282 water samples for which stable isotopes oxygen-18 (18O) and deuterium (2H) are available. The latter involves precipitations (three rain gauges), surface water (five rivers) and groundwater (twenty wells) from five selected alluvial fans. The study confirms that the different isotopic signatures characterizing rain and river water from this area can be exploited for preliminary characterization of their significanc...
Geosciences
Hazard reduction policies include seismic hazard maps based on probabilistic evaluations and the ... more Hazard reduction policies include seismic hazard maps based on probabilistic evaluations and the evaluation of geophysical parameters continuously recorded by instrumental networks. Over the past 25 centuries, a large amount of information about earthquake precursory phenomena has been recorded by scholars, scientific institutions, and civil defense agencies. In particular, hydrogeologic measurements and geochemical analyses have been performed in geofluids in search of possible and reliable earthquake precursors. Controlled experimental areas have been set up to investigate physical and chemical mechanisms originating possible preseismic precursory signals. The main test sites for such research are located in China, Iceland, Japan, the Russian Federation, Taiwan, and the USA. The present state of the art about the most relevant scientific achievements has been described. Future research trends and possible development paths have been identified and allow for possible improvements i...
Geosciences
Shear tests on quartz rocks and single quartz crystals have been conducted to understand the poss... more Shear tests on quartz rocks and single quartz crystals have been conducted to understand the possible relationship between the intensity of detectable stress in fault areas and the energy released in the form of electromagnetic waves in the range 30 KHz-1 MHz (LF–MF). For these tests, a new type of piston-cylinder has been developed, instrumented to collect the electromagnetic signals generated by the quartz during shear stress tests and that allows energy measurements on electromagnetic emissions (EMR) to be performed. The data obtained indicate that shear-stressed quartz crystals can generate electromagnetic emissions in the LF–MF range. These emissions represent a tiny fraction of the total energy dissipated in the fracturing process. The spectrum of radio emissions consists of continuous radiation and overlapping peaks. For the first time, a characteristic migration of peak frequencies was observed, proportional to the evolution of the fracturing process. In particular, the cont...
Physics and Chemistry of the Earth
In this work we analyze the geoelectrieal and geochemical time series jointly recorded by means o... more In this work we analyze the geoelectrieal and geochemical time series jointly recorded by means of Tramutola station dating the period January 1995-September 1996. Since 1991 a research activity devoted to the analysis of geophysical and geochemical time series measured in a test site located in Southern Italy has been carried out. Alter a preliminary screening of spatial and temporal patterns of geochemical and geophysical phenomena observed in the investigated area, some multilmametric automatic stations, able to detect possible precursory phenomena, have been set up close to anomalous fluid emissions in Basilicata (Italy). The stations are equipped with se~ors suitable for C02, 222Rn, electrical conductivity in water, temperature and selfpotential. The main aims of this work are: a) to obtain a emnplete time series of possible precursory parameters; b) to apply statistical methods to discriminate anomalous patterns from background noise; c) to link geophysical and geochemical sJ~a!s; d) to evaluate the possible correlation betwoen anomalous patterns in precursory parameters and the local seismic activity.
Uploads
Papers by Giovanni Martinelli