Giacomo Ulivieri

GECO SRL

Infrasonic array technology has been widely used in the last years for the automatic detection and warning of snow avalanches and operative applications exist in Switzerland, Norway and British Columbia. The authors are currently investigating the capabilities of such a technology for the detection of rockfalls and its use as an early warning syste...

Avalanche occurrences are unambiguous indicators of unstable snow conditions. Information on past and current avalanche activity is therefore crucial for avalanche forecasting. To continuously assess avalanche activity, automatic detection systems are required. In recent years, technological and signal processing advances have led to the developmen...

Infrasound array technology for the detection of snow avalanches was tested at Rogers Pass, BC, Canada over the 2016-17 winter season (24 December 2016 to 11 May 2017). The summit area of Rogers Pass, Glacier National Park was selected as the test location for single array deployment due to its proximal location to avalanches from different aspects...

We present an overview of multiple verification campaigns performed to evaluate the performance of and experience with IDA® (Infrasound Detection of Avalanches) operational systems in Austria, Switzerland, Canada, Norway and the USA. This work focuses on operationally relevant facts and recommendations for the design of infrasound systems. The comp...

Infrasound technology for the detection of snow avalanches was tested at Rogers Pass, BC, Canada over the 2016-17 winter season (24 December 2016 to 11 May 2017). Wyssen Avalanche Control provided a single IDA® infrasound array for this study. The summit area of Rogers Pass, Glacier National Park was selected as the test location for a single infra...

Effusive eruptions at open-conduit volcanoes are interpreted as reactions to a disequilibrium induced by the increase in magma supply. By comparing four of the most recent effusive eruptions at Stromboli volcano (Italy), we show how the volumes of lava discharged during each eruption are linearly correlated to the topographic positions of the effus...

Open-conduit volcanic systems are typically characterized by unsealed volcanic conduits feeding permanent or quasi-permanent volcanic activity. This persistent activity limits our ability to read changes in the monitored parameters, making the assessment of possible eruptive crises more difficult. We show how an integrated approach to monitoring ca...

Infrasound technology for detection of snow avalanches has been tested in mountainous terrain in Norway over the two last winter seasons. Two valleys, Indreeidsdalen and Grasdalen, were selected as test localities for the infrasound arrays because they both are exposed to avalanches from different aspects and several paths. Hence, a detection of an...

Landslides occurring in active volcanic islands play a key role in triggering tsunami and other related risks. Therefore, it becomes vital for a correct and prompt risk assessment to monitor landslides activity and to have an automatic system for a robust early-warning. We then developed a system based on a multi-frequency analysis of seismic signa...

Avalanche risk management is strongly related to the ability to identify and timely report the occurrence of snow avalanches. Infrasound has been applied to avalanche research and monitoring for the last 20 years but it never turned into an operational tool to identify clear signals related to avalanches. We present here a method based on the analy...

Effusive eruptions are explained as the mechanism by which volcanoes restore the equilibrium perturbed by magma rising in a chamber deep in the crust. Seismic, ground deformation and topographic measurements are compared with effusion rate during the 2007 Stromboli eruption, drawing an eruptive scenario that shifts our attention from the interior o...

Avalanche risk management is strongly related to the ability to identify and timely report the occurrence of snow avalanches. Infrasound has been applied to avalanche research and monitoring for the last 20 years but it never turned into an operational tool for the ambiguity to identify clear signals related to avalanches. We present here a new met...

3 Struttura assetto idrogeologico dei bacini montani – Ufficio Neve e Valanghe, Regione Autonoma Valle d'Aosta, Quart (AO) -Italy; ABSTRACT: Since 2009 and within the Operational programme Italy-France (Alps ALCOTRA) – Pro-jects "DynAval" (2009-2012) and "Map 3 " (2012-2014), infrasonic array technology is tested in Aosta Valley to real-time detect...

We report additional radon data collected at Stromboli during 2002–2007. The whole data set of periodic measurements has been systematically analyzed to retrieve the values of background, threshold and anomaly for all the stations of the network. Maps of radon concentrations in space and time correlate with changes in volcanic activity. Higher rado...

We present the analysis of ~4 million infrasonic signals which include 39 episodes of lava fountains recorded at 5.5 km from the active vents. We show that each eruptive episode is characterized by a distinctive trend in the amplitude, waveform, and frequency content of the acoustic signals, reflecting different explosive levels. Lava fountain star...

Monitoring of small-to-medium sized avalanches activity represents a crucial parameter to compare predictions and real effects. However, at present natural avalanche activity is mainly based on field observations, which have a limited range and are possible only during the daylight. Since 2009, the Department of Earth Sciences of University of Flor...

Risk assessment of snow avalanches is mostly related to weather conditions and snow cover. However a robust risk validation requires to identify all avalanches occurring, in order to compare predictions to real effects. For this purpose on December 2010 we installed a permanent 4-element, small aperture (100 m), infrasound array in the Alps, after...

Volcano ash-eruptions produce devastating consequences for local communities and the air transport. Here we present the results of the real-time monitoring of the 2011-2012 sequences of lava fountains eruptions at Etna volcano (Italy) by means of small-aperture (250 m) infrasonic array located at 5 km of distance from the active vents. Most of the...

Electrical resistivity and passive seismic methodologies are powerful tools for geothermal exploration, helping to constrain the geologic framework and the physical parameters of the geothermal system. We investigated the hydrogeological system of the Canino area (Viterbo - Central Italy) in order to constrain the depth of the reservoir rocks for p...

Risk assessment of snow avalanches is mostly related to weather conditions and snow cover. However, a robust risk validation requires avalanche activity data, in order to compare predictions to actual events. For this purpose in December 2009 we installed a temporary 4-element, small aperture (150m), infrasound array in the northwestern Italian Alp...

Volcanoes are efficient radiators of infrasonic waves, as gas volumes rapidly expanding in the atmosphere generate pressure perturbations able to propagate up to thousands of kms away. The intensity of infrasound produced can range from very low amplitude pressure signals (mPa) to violent shock waves (MPa) and its frequency content as well can span...

We present a combined analysis of geochemical and geophysical data collected at Stromboli volcano during the 2005-2007 transition from mild-high explosive to effusive activity. Soil radon concentrations have been compared with the main geophysical parameters. The coherent trend of all considered data allow us to infer the presence, at Stromboli, of...

Infrasonic data collected at Villarrica volcano (Chile) in March 2009 show a sustained, continuous, infrasonic oscillation (tremor) with a monochromatic low frequency content at ∼0.75 Hz. This tremor is extremely stable in time both at the summit and at a distal (∼4 km) small aperture array. Infrasonic tremor is characterized by discrete high ampli...

Risk assessment of snow avalanches is mostly related to weather conditions and snow cover. However a robust risk validation requires to identify all avalanches occurring, in order to compare predictions to real effects. For this purpose on December 2009 we installed a temporary 4-element, small aperture (100 m), infrasound array in the Alps. The ar...

Infrasound is the low-frequency component of sound, ranging from 0.001 to about 20 hertz, below the human threshold of hearing. Many natural phenomena such as earthquakes, avalanches, landslides, tornadoes, and tsunamis are efficient sources of infrasound. Explosive volcanic eruptions typically show a huge column of ash and debris ejected into the...

1] On multi-vents volcanoes changes in activity between different vents reflect a complex fluid-dynamics of the shallow feeding systems and are often explained numerically and experimentally in terms of conduit branches and bifurcations. We present new geophysical constraints on the shallow feeding system of Etna volcano derived from array analysis...

Explosive volcanic eruptions typically show a huge column of ash and debris ejected into the stratosphere, crackling with lightning. Yet equally hazardous are the fast moving avalanches of hot gas and rock that can rush down the volcano's flanks at speeds approaching 280 kilometers per hour. Called pyroclastic flows, these surges can reach temperat...

We used a network of stations to perform systematic radon surveys at Stromboli volcano. The time series of periodic measurements show that monthly average 222Rn emissions reflect changes in volcanic activity and exhibit increasing trends prior and during the last major eruptive cycles. Maps of radon emissions indicate that diffuse degassing is oper...

The Stromboli volcano erupted on February 27, 2007, after an intense Strombolian activity lasted about 2 months. The eruption was characterized by a series of rapidly evolving phenomena, like the propagation of an effusive fracture along the crater rim, the opening of lateral effusive vents, an unusually large effusive flux (>10 m3/s), the collapse...

We present infrasonic data from Etna volcano during 2006-2008 collected with two small-aperture infrasonic arrays deployed at distances of ~1.5 and ~5 km from the active craters, for activity spanning from sustained intermittent degassing to Strombolian explosions, sustained fire fountaining events and opening of explosive fissures. To locate and d...

Stromboli Island, located in the southern Tyrrhenian Sea, is the emerged part (about 900 meters above sea level) of an approximately 3-kilometer-high stratovolcano. Its persistent Strombolian activity, documented for more than 2000 years, is sometimes interrupted by lava effusions or major explosions. Despite the number of recently published geophy...

The persistent mild explosive activity of Stromboli is explained in terms of the dynamics of large gas slugs that ascend the magma conduit to burst at the free surface. This simple physical model has now strong evidence from both geophysical and geochemical viewpoints. In recent years, combined analyses of geophysical data, such as infrasound and t...

The 2002–2003 effusive eruption of Stromboli volcano represents an excellent opportunity to investigate the transition from effusive to explosive activity at an open-conduit basaltic system, when activity migrated from effusive vents, at the base of the craters, to summit explosions. The transition is investigated here through the analysis of very...

Stromboli is an open conduit volcano characterized by persistent conduit degassing and explosive dynamics. During the 2003 effusive eruption we monitored this activity with a five-element array deployed at ∼450 m from the active craters. The array allows us to track in real time changes of explosive activity in terms of source position and excess p...

Infrasound at Stromboli consists on transients related to explosions and on small amplitude intermittent pulses associated with "active" over-pressurized degassing of the magma column. Degassing of a magmatic system is generally understood as a quasi-steady "non-explosive" passive mechanism, when the slow exsolution process allows the continuous co...

Infrared thermometry is a powerful tool to monitor the explosive strombolian activity and to obtain new constrains on its driving source process. The daily explosive activity of Stromboli volcano (Italy) is monitored using a thermal infrared camera installed at 450 meters from the active vents. Video stream is recorded and analyzed in real-time at...

The persistent explosive activity of Stromboli volcano (Italy) ceased in December 2002 and correlated with the onset of a seven-month-long effusive eruption on the volcano flank from new vents that opened just below the summit craters. We intensively monitored this effusive event, collecting and interpreting, in real time, an extensive multiparamet...

The date 28 December 2002, heralded the onset of a 7-month-long effusive eruption at Stromboli volcano in Italy. The onset was accompanied on 30 December by a large landslide (Figure 1). This landslide produced a tsunami that damaged the villages on Stromboli and affected coastal zones around the southern Tyrrhenian Sea. Following the landslide, th...

The Dec. 2002 eruption of Stromboli volcano was followed by almost six months of lava flow characterized by several effusive vents active in the Sciara del Fuoco, at an elevation of 650 m and by the absence of explosive activity at the summit craters. At the end of May 2003, the effusion rate decreased leading to a transition from the effusive to t...

On December 28, 2002, after several days of sustained strong explosive activity, an extremely fast lava flow run over the NE crater rim along the flank of Sciara del Fuoco partially filling the small basin at 650 m a.s.l. and reaching the sea in few minutes. A couple of days later, on December 30, with the lava still flowing out, a large landslide...

On October 31st, 2003, an earthquake Ml 5.4 shocked the South-Central part of Italy, and particularly the Molise and Puglia Regions. A lot of buildings were damaged in the municipalities of San Giuliano di Puglia, Colletorto, Larino and other small towns. In order to examine the influence of site effects and of structural characteristics on damage...

In the San Giuliano di Puglia area (Southern Apennines, Italy), a strong seismic sequence has been activated by two main shocks (Ml=5.3 and Ml=5.2 on 31/10/02 and 1/11/02, respectively). The DIC in Florence, in a joint action with the IGT in Prato (PO), monitored the seismic and the electrical (Self Potential, SP) activity in the epicentral area du...

Cruise STR06 on R/V Urania was performed in the framework of the ”INGV - DPC V2 - Monitoring and research activity at Stromboli and Panarea - Unit V2/03”, and resulted as a joint initiative between CNR (IAMC, Napoli and ISMAR, Bologna), INGV (Roma2, Osservatorio Vesuviano, Catania, Gibilmanna-CNT), University of Firenze and DPC, aiming to produce a...

From 25 November to 2 December 2006, the first active seismic tomography experiment at Stromboli volcano was carried out with the cooperation of four Italian research institutions. Researchers on board the R/V Urania of the Italian National Council of Research (CNR), which was equipped with a battery of four 210- cubic- inch generated injection air...