ALBERT

Description: The Coroglio tuff cliff, having an approximative surface of 35*10^3 m^2 (140m high and 250m wide), represents a unique geophysical field laboratory. The Coroglio coastal cliff, located in Naples, prevalently faces the Pozzuoli Bay (Tyrrhenian Sea) with a SW orientation and it is subject to very variable weather condition. The cliff surface is characterized by the presence of several fractured welded tuff and rock blocks. In order to monitor the dynamic behaviour of the site, a tri-axial velocimeter has been installed on the Coroglio tuff cliff since 2015. It was located on the cliff free surface at a height of 90.0 meters. The scope is to record vibrations propagating in the medium and to analyse a possible correlation with natural events and/or anthropic activities occurring in the area. This would provide, in principle, the possibility of detecting a typical frequency response for the cliff. The seismic sensor has been set to record minimum and maximum values, recorded every 60 seconds on each component. Here we present the maximum absolute velocity values recorded in a 3-years period (July 2015 - July 2018), resulting in 4320 values each day.

Description: Opening of fractures and deformation of rock blocks can lead to potentially hazardous rock failures on coastal cliffs. Here we present a time series of ground deformation measurements within selected tuff blocks located at the Coroglio coastal cliff (Naples) in Italy, over a 4-year period (Dec 2014-Oct 2018). The Coroglio cliff is 140 m high and 250 m wide, and is exposed towards the SW, facing the Pozzuoli Bay (Tyrrhenian Sea). The cliff rockface is represented by fractured welded tuff (Neapolitan Yellow Tuff fm.), and includes several rock fronts exceeding 50 m in height. Measurements were acquired along fractures and stratal discontinuities bounding the selected unstable tuff blocks, in order to assess the pattern and magnitude of block deformations (fracture opening and block rotational and/or traslative movements) and their evolution through time. The monitoring system is composed of 8 crackmeters and 2 tiltmeters equipped with internal thermometers, that have been set with a sampling rate of one measurement each 30 minutes, resulting in 48 measurements per day.

Description: Weather data monitoring is ongoing since 2013 in a network of three sites located in the Campi Flegrei volcanic area, near Naples (Italy) in the framework of the MONICA (Innovative Monitoring of Coastal and Marine Environment) Project. The aim of this activity is to acquire time series to analyze the influence of meteorological factors on geomorphological coastal processes, such as cliff retreat, landslides and beach erosion. The uploaded dataset includes data (temperature, relative humidity, wind, barometric pressure and rain) acquired at the Bacoli automatic weather station(model: DAVIS Vantage Pro2 wireless) during the period Dec. 2013 - Oct. 2018. Automatic data transfer from the weather station to the ISMAR-CNRprocessing center of Naples is performed by an internet LAN connection.

Description: Weather data monitoring is ongoing since 2013 in a network of three sites located in the Campi Flegrei volcanic area, near Naples (Italy) in the framework of the MONICA (Innovative Monitoring of Coastal and Marine Environment) Project. The aim of this activity is to acquire time series to analyze the influence of meteorological factors on geomorphological coastal processes, such as cliff retreat, landslides and beach erosion. The uploaded dataset includes data (temperature, rain, wind, barometric pressure and humidity) acquired at the Capo Posillipo automatic weather station (model DAVIS Vantage Pro2 wireless) during the period Dec. 2013 - Oct. 2018. The station is located in the western sector of the urban area of Naples (Italy). Automatic data transfer from the weather station to the ISMAR-CNR processing center, located in the Naples harbor, is routinely performed via an Internet LAN connection.

Description: Rapid evaluation of strong ground-shaking maps after moderate-to-large earthquakes is crucial to recognizing those areas where the largest damage and losses are expected. These maps play a fundamental role for emergency management. This is particularly important for areas having high seismic risk potential and covered by dense seismic networks. In near-real-time applications, ground-shaking maps are produced by integrating recorded data and estimates obtained by using ground-motion predictive equations, which assume point-source models. However, particularly for large earthquakes, improvements in the predictions of the peak ground motion can be obtained when fault extension and orientation are available. In fact, detailed source information allows one to use a more robust source-to-site distance metric compared with hypocentral distance.In this paper, a technique for estimating both fault extent (in terms of its surface projection) and dominant rupture direction is presented. This technique can be used in near-real-time ground-motion map calculation codes with the aim of improving ground-motion estimates with respect to a point-source model. The model parameters are estimated by maximizing a probability density function based on the residuals between observed and predicted peak-ground-motion quantities, the latter obtained by using predictive equations. The model space to be investigated is defined through a Bayesian approach, and it is explored by a grid-searching technique. The effectiveness of the proposed technique is demonstrated by offline numerical tests using data from three earthquakes occurring in different seismotectonic environments. The selected earthquakes are the 17 August 1999 Mw 7.5 Kocaeli (Turkey) earthquake, the 6 April 2009 Mw 6.3 L’Aquila (Italy) earthquake, and the 17 January 1994 Mw 6.7 Northridge (California) earthquake. The obtained results show that the proposed technique allows for fast and first order estimates of the fault extent and dominant rupture direction, which could be used to improve ground-shaking map calculations.

Description: Along the coastline of the Campi Flegrei volcanic district, near Naples (Italy), severe retreat processes affect a large part of the coastal cliffs, mainly made of fractured volcanic tuff and pyroclastic deposits. Progressive fracturing and deformation of rocks can lead to hazardous sudden slope failures on coastal cliffs. Among the triggering mechanisms, the most relevant are related to meteorological factors, such as precipitation, freezing conditions, and thermal expansion due to solar heating of rock surfaces. In this paper, we present a database of measurement time series taken over a period of ∼ 4 years (Dec 2014–Oct 2018), referred to the deformations of selected tuff blocks in the Coroglio coastal cliff. The monitoring system is implemented on five unstable tuff blocks and is formed by nine crackmeters and two tiltmeters equipped with internal thermometers. The system is coupled with a total weather station, measuring rain, temperature, wind and atmospheric pressure operating since January 2014 up to Dec 2018. A measurement frequency of 10 and 30 minutes has been respectively set for meteorological and deformation sensors. The aim of the measurements is to assess the magnitude and temporal pattern of rock block deformations (fracture opening and block movements) before block failure and their correlation with selected meteorological parameters. The results of a multivariate statistical analysis of the measured time series suggest a close correlation between temperature and deformation trends. The recognized cyclic, sinusoidal changes in the width (opening/closing) of fractures and tuff blocks rotations are ostensibly linked to multiscale (i.e. daily, seasonal and annual) temperature variations. Some trends of cumulative multi-temporal changes have been also recognized. The full databases are freely available online at https://doi.org/10.1594/PANGAEA.896000 (Matano et al., 2018) and https://doi.org/10.1594/PANGAEA.899562 (Fortelli et al., 2019).

Description: A hazard assessment of the 1976 Guatemala earthquake (M = 7.5) was conducted to achieve a better definition of the seismic hazard. The assessment was based on the environmental effects that had effectively contributed to the high destructive impact of that event. An interdisciplinary approach was adopted by integrating: (1) historical data; (2) co-seismic geological effects in terms of Environmental Seismic Intensity (ESI) scale intensity values; and (3) ground shaking data estimated by a probabilistic/deterministic approach. A detailed analysis of primary and secondary effects was conducted for a set of 24 localities, to obtain a better evaluation of seismic intensity. The new intensity values were compared with the Modified Mercalli Intensity (MMI) and Peak Ground Acceleration (PGA) distribution estimated using a probabilistic/deterministic hazard analysis approach for the target area. Our results are evidence that the probabilistic/deterministic hazard analysis procedures may result in very different indications on the PGA distributions. Moreover, PGA values often display significant discrepancy from the macroseismic intensity values calculated with the ESI scale. Therefore, the incorporation of the environmental earth effects into the probabilistic/deterministic hazard analysis appears to be mandatory in order to achieve a more accurate seismic estimation.

Description: Along the coastline of the Phlegraean Fields volcanic district, near Naples (Italy), severe retreat processes affect a large part of the coastal cliffs, mainly made of fractured volcanic tuff and pyroclastic deposits. Progressive fracturing and deformation of rocks can lead to hazardous sudden slope failures on coastal cliffs. Among the triggering mechanisms, the most relevant are related to meteorological factors, such as precipitation and thermal expansion due to solar heating of rock surfaces. In this paper, we present a database of measurement time series taken over a period of ∼4 years (December 2014–October 2018) for the deformations of selected tuff blocks in the Coroglio coastal cliff. The monitoring system is implemented on five unstable tuff blocks and is formed by nine crackmeters and two tiltmeters equipped with internal thermometers. The system is coupled with a total weather station, measuring rain, temperature, wind and atmospheric pressure and operating from January 2014 up to December 2018. Measurement frequencies of 10 and 30 min have been set for meteorological and deformation sensors respectively. The aim of the measurements is to assess the magnitude and temporal pattern of rock block deformations (fracture opening and block movements) before block failure and their correlation with selected meteorological parameters. The results of a multivariate statistical analysis of the measured time series suggest a close correlation between temperature and deformation trends. The recognized cyclic, sinusoidal changes in the width (opening–closing) of fractures and tuff block rotations are ostensibly linked to multiscale (i.e., daily, seasonal and annual) temperature variations. Some trends of cumulative multi-temporal changes have also been recognized. The full databases are freely available online at: https://doi.org/10.1594/PANGAEA.896000 (Matano et al., 2018) and https://doi.org/10.1594/PANGAEA.899562 (Fortelli et al., 2019).