Evaluation of Probabilistic Site‐Specific Seismic‐Hazard Methods and Associated Uncertainties, with Applications in the Po Plain, Northern Italy

2015 ◽  
Vol 105 (5) ◽  
pp. 2787-2807 ◽  
Author(s):  
Ezio Faccioli ◽  
Roberto Paolucci ◽  
Manuela Vanini
Author(s):  
Claudia Mascandola ◽  
Simone Barani ◽  
Marco Massa ◽  
Dario Albarello

ABSTRACT This study investigates and quantifies the influence of the shallower deposits (down to few hundreds of meters) of the Po Plain sedimentary basin (northern Italy) on the long-period component (i.e., 1  s<T<3  s) of seismic ground motion, in which amplification effects due to the soft sediments above seismic bedrock were observed. A new seismostratigraphic model of the shallow deposits of the entire basin is provided with an unprecedented detail by taking advantage of recently acquired geophysical data. The seismostratigraphic model is used to simulate the ground motion amplification in the Po Plain by means of extensive 1D ground response analysis. Results are compared with seismic observations available at a number of sites equipped with borehole seismic stations, where earthquakes have been recorded both at the surface and at the seismic bedrock depth. Despite the general agreement with observations concerning the seismic resonance frequencies, our model may fail in capturing the amplitude of the actual seismic amplification of the basin in the long-period range. We observe that 3D basin effects related to surface waves generated at the edge of the basin may play a significant role in those zones where seismic hazard is controlled by distant sources. In these cases, 1D modeling leads to average underestimations of 30%, up to a maximum of 60%. The amplification functions need to be corrected for a basin-effects correction term, which in this case is provided by the ground-motion prediction equation of the study area. The corrected amplification functions agree with the empirical observations, overcoming the uneven distribution of the recording stations in strong-motion datasets. These results should be taken into account in future seismic microzonation studies in the Po Plain area, where the 1D approach is commonly adopted in ground response analyses, and in site-specific seismic hazard assessments aimed at the design of structures that are sensitive to the long-period component of seismic ground motion (e.g., long-span bridges and tall buildings).


Ecohydrology ◽  
2011 ◽  
Vol 4 (4) ◽  
pp. 597-607 ◽  
Author(s):  
V. Marconi ◽  
M. Antonellini ◽  
E. Balugani ◽  
E. Dinelli

Sedimentology ◽  
2021 ◽  
Author(s):  
Luigi Bruno ◽  
Alessandro Amorosi ◽  
Stefano Lugli ◽  
Irene Sammartino ◽  
Daniela Fontana

2016 ◽  
Vol 48 (1) ◽  
pp. 9 ◽  
Author(s):  
Stefano Mammola ◽  
Riccardo Cavalcante ◽  
Marco Isaia

The diving bell spider <em>Argyroneta aquatica</em> is the only known spider to conduct a wholly aquatic life. For this reason, it has been the object of an array of studies concerning different aspects of its peculiar biology such as reproductive behavior and sexual dimorphism, physiology, genetic and silk. On the other hand, besides some empirical observations, the autoecology of this spider is widely understudied. We conducted an ecological study in a resurgence located in the Po Plain (Northern Italy, Province of Vercelli) hosting a relatively rich population of <em>Argyroneta</em> <em>aquatica</em>, aiming at identifying the ecological factors driving its presence at the micro-habitat level. By means of a specific sampling methodology, we acquired distributional data of the spiders in the study area and monitored physical-chemical and habitat structure parameters at each plot. We analyzed the data through Bernoulli Generalized Linear Models (GLM). Results pointed out a significant positive effect of the presence of aquatic vegetation in the plot. In addition, the presence of <em>A. aquatica</em> was significantly associated with areas of the resurgence characterized at the same time by high prey availability and low density of predators. Considering the ecological importance and rarity of this species, we update and revise the data on the distribution of <em>A. aquatica</em> in Italy.


2012 ◽  
Vol 55 (4) ◽  
Author(s):  
Giuliana Alessio ◽  
Laura Alfonsi ◽  
Carlo Alberto Brunori ◽  
Pierfrancesco Burrato ◽  
Giuseppe Casula ◽  
...  

<p>On May 20, 2012, a Ml 5.9 seismic event hit the Emilia Po Plain, triggering intense earthquake activity along a broad area of the Po Plain across the provinces of Modena, Ferrara, Rovigo and Mantova (Figure 1). Nine days later, on May 29, 2012, a Ml 5.8 event occurred roughly 10 km to the SW of the first main shock. These events caused widespread damage and resulted in 26 victims. The aftershock area extended over more than 50 km and was elongated in the WNW-ESE direction, and it included five major aftershocks with 5.1 ≤Ml ≤5.3, and more than 2000 minor events (Figure 1). In general, the seismic sequence was confined to the upper 10 km of the crust. Minor seismicity with depths ranging from 10 km to 30 km extended towards the southern sector of the epicentral area (ISIDe, http://iside.rm.ingv.it/). […]</p><br />


2012 ◽  
Vol 55 (1) ◽  
Author(s):  
Marco Massa ◽  
Gabriele Ameri ◽  
Sara Lovati ◽  
Rodolfo Puglia ◽  
Gianlorenzo Franceschina ◽  
...  

<p>This note focuses on the ground motion recorded during the recent moderate earthquakes that occurred in the central part of northern Italy (Panel 1), a region that is characterized by low seismicity. For this area, the Italian seismic hazard map [Stucchi et al. 2011] assigns a maximum horizontal acceleration (rock site) of up to 0.2 g (10% probability of being exceeded in 50 yr). In the last 4 yr, this region has been struck by 9 earthquakes in the magnitude range 4 <span>≤</span>M<span>w </span><span>≤</span> 5.0, with the three largest located in the Northern Apennines (the M<span>w </span>4.9 and 5.0 Parma events, in December 2008 and January 2012) and on the Po Plain (the M<span>w </span>4.9 Reggio Emila event, in January 2012). We have analyzed the strong-motion data (distance &lt;300 km) from these events as recorded by stations belonging to the Istituto Nazionale di Geofisica e Vulcanologia (RAIS, http://rais.mi.ingv.it; RSNC, http://iside.rm.ingv.it) and the Department of Civil Protection (RAN, www.protezionecivile.it; http://itaca.mi.ingv.it). […]</p>


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