Seismic velocity precursors to the 2016 Mw 6.5 Norcia (Italy) earthquake

Geology ◽  
2020 ◽  
Vol 48 (9) ◽  
pp. 924-928 ◽  
Author(s):  
C. Chiarabba ◽  
P. De Gori ◽  
M. Segou ◽  
M. Cattaneo

Abstract Earthquakes occur as the result of long-term strain accumulation on active faults and complex transient triggering mechanisms. Although laboratory experiments show accelerating deformation patterns before failure conditions are met, imaging similar preparatory phases in nature remains difficult because it requires dense monitoring in advance. The 2016 Amatrice-Visso-Norcia (central Italy) earthquake cascade, captured by an unprecedented seismic network, provided a unique testing ground to image the preparatory phase of a large event. The crustal volume of the Norcia incipient fault was densely illuminated by seismic rays from more than 13,000 earthquakes that occurred within the 3 mo before the main shock nucleation. We performed seismic tomography in distinct time windows that revealed the precursory changes of elastic wave speed, signaling (1) the final locked state of the fault, and (2) the rapid fault-stiffness alterations near the hypocenter just a few weeks before the event. The results are the first instance where short-lived, hard-to-catch crustal properties shed light on evolving earthquake cascades.

2018 ◽  
Vol 34 (4) ◽  
pp. 1557-1583 ◽  
Author(s):  
Fabrizio Galadini ◽  
Emanuela Falcucci ◽  
Stefano Gori ◽  
Paolo Zimmaro ◽  
Daniele Cheloni ◽  
...  

The Central Italy earthquake sequence produced three main shocks: M6.1 24 August, M5.9 26 October, and M6.5 30 October 2016. Additional M5–5.5 events struck this territory on 18 January 2017 in the Campotosto area. Fault plane solutions for the main shocks exhibit normal faulting (characteristic of crustal extension occurring in the inner central Apennines). Significant evidence, including hypocenter locations, strike and dip angles of the moment tensors, inverted finite fault models (using GPS, interferometric aperture radar, and ground motion data), and surface rupture patterns, all point to the earthquakes having been generated on the Mt. Vettore–Mt. Bove fault system (all three main shocks) and on the Amatrice fault, in the northern sector of the Laga Mountains (portion of 24 August event). The earthquake sequence provides examples of both synthetic and antithetic ruptures on a single fault system (30 October event) and rupture between two faults (24 August event). We describe active faults in the region and their segmentation and present understanding of the potential for linkages between segments (or faults) in the generation of large earthquakes.


2016 ◽  
Vol 59 ◽  
Author(s):  
Simone Marzorati ◽  
Marco Cattaneo ◽  
Massimo Frapiccini ◽  
Giancarlo Monachesi ◽  
Chiara Ladina

The seismicity of the last four years before the August 24 2016 01:36 UTC M<sub>W</sub> 6.0 earthquake that struck central Italy is presented with the aim to understand the preparatory phase of the event. In contrast with the 2009 L’Aquila earthquake that was preceded by a seismic sequence and the 2013-2015 Gubbio seismic swarm that, to date, is ended without any strong event, our preliminary results don’t show seismic sequences in the last months previous the mainshock of the August 24 2016 and a low similarity between seismicity clusters in the last four years and the foreshocks.


2017 ◽  
Vol 174 (10) ◽  
pp. 3673-3688 ◽  
Author(s):  
Alessandro Piscini ◽  
Angelo De Santis ◽  
Dedalo Marchetti ◽  
Gianfranco Cianchini

2021 ◽  
pp. 1420326X2110036
Author(s):  
Qian Xu ◽  
Chan Lu ◽  
Rachael Gakii Murithi ◽  
Lanqin Cao

A cohort case–control study was conducted in XiangYa Hospital, Changsha, China, which involved 305 patients and 399 healthy women, from June 2010 to December 2018, to evaluate the association between Chinese women’s short- and long-term exposure to industrial air pollutant, SO2 and gynaecological cancer (GC). We obtained personal and family information from the XiangYa Hospital electronic computer medical records. Using data obtained from the air quality monitoring stations in Changsha, we estimated each woman’s exposure to the industrial air pollutant, sulphur dioxide (SO2), for different time windows, including the past 1, 5, 10 and 15 years before diagnosis of the disease. A multiple logistic regression model was used to assess the association between GC and SO2 exposure. GC was significantly associated with long-term SO2 exposure, with adjusted odds ratio (95% confidence interval) = 1.56 (1.10–2.21) and 1.81 (1.07–3.06) for a per interquartile range increase in the past 10 and 15 years, respectively. Sensitivity analysis showed that different groups reacted in different ways to long-term SO2 exposure. We concluded that long-term exposure to high concentration of industrial pollutant, SO2 is associated with the development of GC. This finding has implications for the prevention and reduction of GC.


2019 ◽  
Vol 9 (22) ◽  
pp. 4813 ◽  
Author(s):  
Hanbo Yang ◽  
Fei Zhao ◽  
Gedong Jiang ◽  
Zheng Sun ◽  
Xuesong Mei

Remaining useful life (RUL) prediction is a challenging research task in prognostics and receives extensive attention from academia to industry. This paper proposes a novel deep convolutional neural network (CNN) for RUL prediction. Unlike health indicator-based methods which require the long-term tracking of sensor data from the initial stage, the proposed network aims to utilize data from consecutive time samples at any time interval for RUL prediction. Additionally, a new kernel module for prognostics is designed where the kernels are selected automatically, which can further enhance the feature extraction ability of the network. The effectiveness of the proposed network is validated using the C-MAPSS dataset for aircraft engines provided by NASA. Compared with the state-of-the-art results on the same dataset, the prediction results demonstrate the superiority of the proposed network.


Thorax ◽  
2019 ◽  
Vol 74 (7) ◽  
pp. 715-717 ◽  
Author(s):  
Jesus Gonzalez-Bermejo ◽  
Jean-Paul Janssens ◽  
Claudio Rabec ◽  
Christophe Perrin ◽  
Frédéric Lofaso ◽  
...  

Episodes of patient-ventilator asynchrony (PVA) occur during acute and chronic non-invasive positive pressure ventilation (NIV). In long-term NIV, description and quantification of PVA is not standardised, thus limiting assessment of its clinical impact. The present report provides a framework for a systematic analysis of polygraphic recordings of patients under NIV for the detection and classification of PVA validated by bench testing. The algorithm described uses two different time windows: rate asynchrony and intracycle asynchrony. This approach should facilitate further studies on prevalence and clinical impact of PVA in long-term NIV.


2015 ◽  
Vol 6 (2) ◽  
pp. 199-222 ◽  
Author(s):  
Xiaoling Li ◽  
Xingyao Ren ◽  
Xu Zheng

Purpose – This paper aimed to analyze the short- and long-term effects of the breadth and depth of seller competition on the performance of platform companies, and investigated the underlying mechanisms of customers’ two-sided marketing tactics on the structure of the competition between sellers. Design/methodology/approach – A longitudinal research design was adopted by gathering daily market objective data on e-commerce platforms for 250 days, and the dynamic evolution effects was analyzed by using a vector autoregression model which compared the differences between the short- and long-term effectiveness of different customer relationship management (CRM) strategies. Findings – The breadth of competition amongst sellers improves the performance of platforms, whilst the depth of competition among sellers has a positive effect on the short-term performance. However, it has a negative effect on the long-term performance of their platforms. In both the short and long terms, advertising tactics that attract new buyers contribute more to increases in the breadth of seller competition than those that attract existing buyers do. Subsidies for new sellers decrease the depth of seller competition more than those for old sellers. Research limitations/implications – Further research could be undertaken to investigate the validity of marketing tactics other than advertising tactics, and thus expand the time windows of the available data. Practical implications – It is imperative for platform companies to implement effective control over seller competition to balance the interests of the sellers and of themselves. Originality/value – The dyadic paradigm of CRM research has been extended by considering the perspective of the electronic platform company, how the tactics of exploitation and exploration of two-sided customers impact upon seller competitive structures have been delved into and why new customers have a unique value to platform companies has been identified.


2017 ◽  
Vol 174 (10) ◽  
pp. 3663-3672 ◽  
Author(s):  
Vincenzo Convertito ◽  
Raffaella De Matteis ◽  
Nicola Alessandro Pino

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