299 research outputs found
A Questionnaire Survey of the Earthquake Network App's Users in Peru Following an M8 Earthquake in 2019
Get PDFThe 'Earthquake Network’ (EQN) is an app which detects earthquakes by creating an ad-hoc network of smartphone's accelerometer sensors and provides early warnings of earthquakes via the same smartphone app.
The EMSC (Euro-Mediterranean Seismological Centre) and the University of Bergamo conducted an online survey, following an earthquake of magnitude M8 on 2019-05-26 07:41:13.6 UTC in Northern Peru with epicentre (5.81S, 75.27W). This survey targeted EQN users in the felt area of the earthquakes and was conducted from 2019-07-23 to 2019-08-18. It aimed at assessing users’ understanding and reaction to the EQN early warning for this specific earthquake.
The questionnaire was written in Spanish since it is the most commonly spoken language in the studied area. Individuals who use the app in Spanish were invited to complete the survey via an advertisement on the Earthquake Network app. A PDF containing the questionnaire and the relationship between the questions is included in this archive. 3805 respondents took the survey, including 2 719 that were actually in the area at the time.
The analysis: Results derived from this dataset will be included as part of a submitted Science article (Bossu et al. '“Shaking in 5 seconds!” A Voluntary Smartphone-based Earthquake Early Warning System', 2021) to show that respondents received notifications from the Earthquake Network App before feeling the shaking but also that many did not immediately “drop, hold and cover' and were too intent on warning those close to them of the impending danger. All respondents consented that their data could be used for research purposes. The EMSC and University of Bergamo made sure not to collect or diffuse personal data.
The dataset is a zip-file that contains the questionnaire responses as a comma-separated text file (csv) and a pdf containing a representation of the questionnaire that was presented to respondents
Use of calcium-containing endodontic sealers as apical barrier in fluid-contaminated wide-open apices.
No full textPurpose: The sealing of wide-open apex roots is still a challenge and requires the use of apical barrier techniques. The aim was to evaluate ex vivo the sealing and the apical morphology of 3 commercial calcium oxide (CaO)-containing sealers - namely, 2 zinc oxide-based (CRCS and Sealapex) and a calcium silicate MTA-based (TechBiosealer Endo) - placed in wet root canals with artificial wide-open apices.
Methods: Thirty human single-rooted teeth were shaped with Protaper and an artificial open apex (diameter size 110) was created. Each root was inserted in a custom-designed support containing simulated body fluid (Hank's balanced salt solution, HBSS) at the bottom simulating the presence of periapical fluid in the canal. Each sealer (TechBiosealer Endo, CRCS, Sealapex) was compacted to the apical 5 mm and the filled roots stored in HBSS at 37°C. The sealing was evaluated as microinfiltrated fluid since 24 hours up to 6 months using a high-precision digital fluid flow meter. The sealers were also studied for setting time in HBSS, calcium releasing (statistical analysis by 2-way ANOVA followed by Student-Newman-Keuls test, P<0.05) and surface morpho-chemistry by ESEM-EDX and OM analysis.
Results: All sealers showed a stable seal. TechBiosealer Endo maintained a better seal than the other materials (P<0.05) and ESEM-EDX and OM analyses showed the presence of apatite deposits.
Conclusions: The clinical use of hydraulic hydrophilic MTA-based sealers can be recommended to stop/reduce the fluid flow rate through the apex. The artificial apical barrier in wet wide apices is a suitable technique able to seal wet root canals
Smartphones enabled up to 58 s strong-shaking warning in the M7.8 Türkiye earthquake
Get PDFPublic earthquake early warning systems (PEEWSs) have the potential to save lives by warning people of incoming seismic waves up to tens of seconds in advance. Given the scale and geographical extent of their impact, this potential is greatest for destructive earthquakes, such as the M7.8 Pazarcik (Türkiye) event of 6 February 2023, which killed almost 60,000 people. However, warning people of imminent strong shaking is particularly difficult for large-magnitude earthquakes because the warning must be given before the earthquake has reached its final size. Here, we show that the Earthquake Network (EQN), the first operational smartphone-based PEEWS and apparently the only one operating during this earthquake, issued a cross-border alert within 12 s of the beginning of the rupture. A comparison with accelerometer and macroseismic data reveals that, owing to the EQN alerting strategy, Turkish and Syrian EQN users exposed to intensity IX and above benefitted from a warning time of up to 58 s before the onset of strong ground shaking. If the alert had been extended to the entire population, approximately 2.7 million Turkish and Syrian people exposed to a life-threatening earthquake would have received a warning ranging from 30 to 66 s in advance
Citizens’ smartphones unravel earthquake shaking in urban areas
Get PDFSeismic shaking maps (known as ShakeMaps) have become an essential tool for assessing the impact of a recent earthquake or for scenario studies of future events. The spatial resolution of ShakeMaps remains low, particularly in urban areas where spatial variations can have a major impact on damage due to varying population density. Smartphones, with their internal accelerometers and widespread use, help to increase the density of seismic recording precisely where the potential impact of the earthquake may be greatest. In this work, we use statistical spatial modelling to show that smartphone measurements collected by the Earthquake Network citizen science initiative allow us to map site amplification at high spatial resolution, generate high-resolution ShakeMaps, and improve existing ground motion models. We apply the method to the red zone of Campi Flegrei, Italy, a high volcanic and seismic risk area with around 500,000 inhabitants and characterised by a complex spatial pattern of site amplification
Efficacy and Usefulness of an Independent Public Earthquake Early Warning System: A Case Study - The Earthquake Network Initiative in Peru
Get PDFPublic earthquake early warning (PEEW) systems are intended to reduce individual risk by warning people ahead of shaking and allowing them to take protective action. Yet very few studies have assessed their actual efficacy from a risk‐reduction perspective. Moreover, according to these studies, a majority of people do not undertake safety actions when receiving the warning.
The spectrum of PEEW systems has expanded, with a greater diversity of actors (from citizens to private companies), increased independence from national authorities, and greater internationality. Beyond differences in warning and messaging strategies, systems’ characteristics may impact the way the public perceive, trust, understand, and respond to these warnings, which in turn will influence PEEW systems’ efficacy and perceived usefulness, enhancing the need for additional research.
We take the example of earthquake network, an independent, voluntary, community‐based and free system that offers a PEEW service. Through a quantitative survey (n = 2625), we studied users’ perception and reaction to a warning sent related to an M 8.0 earthquake in Peru (where no national system existed). We observed that even though only a minority of users actually took protective action, the system was appreciated and perceived as useful by the majority because it enabled mental preparation before the shaking. We found evidence for a tolerance for perceived late, missed, and false alerts. However, because it is a voluntary and independent system, the social dimension of the warning was incomplete because only a fringe of the population benefited from the warning. Therefore, many users’ first reaction was to warn their relatives. We discuss the need for partnerships between PEEW operators and national authorities to guarantee universal access to the service and maximize PEEW system efficacy
“Shaking in 5 Seconds!”—Performance and User Appreciation Assessment of the Earthquake Network Smartphone‐Based Public Earthquake Early Warning System
No full textPublic earthquake early warning systems have the potential to reduce individual risk by warning people of approaching tremors, but their development has been hampered by costly infrastructure. Furthermore, both users’ understanding of such a service and their reactions to actual warnings have been the topic of only a few surveys. The smartphone app of the Earthquake Network initiative utilizes users’ smartphones as motion detectors and provides the first example of a purely smartphone‐based earthquake early warning system, without the need for dedicated seismic station infrastructure and operating in multiple countries. We demonstrate that this system has issued early warnings in multiple countries, including for damaging shaking levels, and hence that this offers an alternative to conventional early warning systems in the foreseeable future. We also show that although warnings are understood and appreciated by users, notably to get psychologically prepared, only a fraction take protective actions such as “drop, cover, and hold.
Analysis of Detections by the Earthquake Network App between 2017-12-15 and 2020-01-31
Get PDFThe 'Earthquake Network’ (EQN) is an app which detects earthquakes by creating an ad-hoc network of smartphones' accelerometer sensors and provides early warnings for earthquakes via the same smartphone app. Detections are not due to individual smartphone measurements but due to near-simultaneous trigger signals from clusters of smartphones running the app. Therefore detections are normally located in the closest populated regions to an earthquake's epicentre. These datasets compare sets of detections with the earthquake parameters published by seismic institutes in order to analyse the performance of the EQN network.
One dataset contains 550 detections made by EQN between 2017-12-15 and 2020-01-31 in Chile, USA and Italy. Wherever possible, each detection was associated with an earthquake from the parameter catalogue of each country's seismic institute (CSN for Chile, USGS for USA and INGV for Italy). Associations were carried out automatically but also checked manually.
The other dataset contains 134 detections from around the world that could be associated to earthquakes with magnitude ≥ M5 or magnitude ≥ M4.5 in Italy and the USA. There are 68 detections that are common to the first dataset. All detections were associated to parameters from the the USGS earthquake parameter catalogue for consistency
A Probabilistic Framework for Modeling the Detection Capability of Smartphone Networks in Earthquake Early Warning
No full textEarthquake early warning systems based on smartphone networks are emerging as complementary systems to the more expensive systems based on scientific-grade instruments. Hence, there is a need to better understand their detection capabilities. This article introduces a probabilistic framework for modeling the interaction between a smartphone network and seismic events to provide estimates of the detection probability for a given earthquake and to assess how the network geometry affects the detection delay. The framework was used to study the detection capability of the first operational smartphone-based earthquake early warning system implemented by the Earthquake Network (EQN) initiative, which started in 2013 and has
issued more than 5500 warnings in 25 countries. The analysis showed that the probability of detection of an earthquake depends on the interaction between the network geometry and the earthquake parameters and that the detection probability is greatly affected by the population spatial distribution. Countries that benefit most from the EQN initiative are those without large gaps in the geographic distribution of their population
Association between age and severity of malocclusion in the pediatric age: a cross-sectional study
Get PDFThe establishment and subsequent worsening of a malocclusion is the result of a combination of factors dominated by the interaction between inheritance and environment and follows a dynamic process of temporal evolution. This transversal study, based on a sample of 579 children from the Caserta area in Southern Italy, investigates the potential worsening of malocclusions with age by measuring the relationship between the severity level of orthodontic abnormalities, evaluated through the IONT-DHC classification, and the age of the subjects. Our results show that a statistically significant association exists (p < 0.0001) between the overall severity of the malocclusion and the age of the subjects, underlining the importance of an early orthodontic prevention and highlighting that large sections of the population still need to be sensitized to orthodontic problems
Results and plans with heavy ion collisions at LHCb experiment
No full textInternational audienceIn 2015, the LHCb experiment has started to acquire data during the ion-ion runs of the LHC. In this talk we present the results of the first data analyses and discuss the prospects for the LHCb ion-ion collision programme
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