On the Integrated Surface Uplift for Dip‐Slip Faults

Interferometric Synthetic Aperture Radar observations often provide maps of vertical displacement that can be integrated to estimate an uplift volume. Relating this measure to source processes requires a model of the deformation. Bignami et al. (2019) argue that the negative uplift volume associated with the 2016 Amatrice–Norcia, central Italy, earthquake sequence requires a coseismic volume collapse of the hanging wall. Using results for dip‐slip dislocations in an elastic half‐space we show that V_(uplift)=(P/4)(1−2ν)sin(2δ) in which P is the seismic potency, ν is the Poisson’s ratio, and δ is the fault dip, consistent with an earlier result of Ward (1986). For reasonable estimates of net potency for the 2016 Amatrice–Norcia sequence, this simple formula yields uplift volume estimates close to that observed. We conclude that the data are completely consistent with elastic dislocation theory and do not require a volume collapse at depth

Treating tobacco addiction. Praxis and barriers amongst Icelandic general practitioners

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenObjective: To assess praxis and identify the most common barriers for engaging in tobacco prevention in general practice in the Nordic countries. Material and methods: All 167 practicing general practitioners in Iceland received a questionnaire at home assessing praxis and barriers for systematic involvement in tobacco prevention. Results: The over all response rate was 77%. Few general practitioners asked patients if they smoked if the patient had no smoking related symptoms. Few supported patients who wanted to stop smoking. However, a big majority agreed that tobacco prevention was a part of their job. The main reasons for not engaging in tobacco prevention was lack of time and the feeling that the time spent may not be worth the effort since few patients quit. A big majority stated that they would prefer to reefer smokers to smoking cessation specialist. Conclusions: Smoking cessation expertise needs to be more accessible to Icelandic patients and doctors.Tilgangur: Að kanna meðferðarvenjur heilsugæslulækna við meðhöndlun á tóbaksfíkn og greina helstu þröskulda (hindranir) sem standa í vegi fyrir því að heilsugæslulæknar á Íslandi sinni tóbaksvörnum. Efniviður og aðferðir: Spurningalisti var sendur heim til allra 167 starfandi heilsugæslulækna á Íslandi vorið 1999. Spurt var um tóbaksvarnastarf, hindranir fyrir að sinna tóbaksvörnum og eigin tóbaksneyslu heilsugæslulækna. Niðurstöður: Svarshlutfall var 77%. Af þeim sem svöruðu reyktu 7% daglega og 14% af og til. Fáir heilsugæslulæknar höfðu það sem reglu að spyrja sjúklinga sín hvort þeir reyktu ef þeir höfðu engin einkenni sem líklegt er að rekja megi til reykinga. Fáir buðu sjúklingum sínum upp á stuðning við að hætta að reykja. Flestir töldu tóbaksvarnir þó vera innan síns verksviðs. Aðalástæðan fyrir að sinna ekki tóbaksvörnum var tímaskortur og sú tilfinning að fáir hætti að reykja þrátt fyrir stuðning. Mikill meirihluti taldi æskilegt að geta vísað reykingamönnum til sérfræðinga í reykbindindi. Ályktanir: Auka þarf aðgengi sjúklinga og heilsugæslulækna að sérfræðingum í reykbindindi

The diversion of prescribed stimulant medications of 10th. graders in Iceland

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesInngangur: Athyglisbrestur og ofvirkni (ADHD) er taugaþroskaröskun sem kemur yfirleitt fram fyrir 7 ára aldur. Örvandi lyf eru mikið notuð til meðhöndlunar á þessum kvilla hér á landi, en fela í sér hættu á ávanabindingu, misnotkun og lyfjaflakki, það er að þau séu notuð af öðrum einstaklingi en þeim sem læknir skrifaði lyfseðil fyrir. Þessari rannsókn var ætlað að svara því hversu algengt slíkt lyfjaflakk væri meðal unglinga á Íslandi. Efniviður og aðferðir: Hér er byggt á gögnum sem safnað var í íslenskum hluta ESPAD-rannsóknarinnar (European School Survey Project on Alcohol and Other Drugs) um vímuefnaneyslu 10. bekkinga. Niðurstöður: Af 2306 nemendum sem tóku þátt í könnunni sögðust 91% (2098) aldrei hafa fengið slík lyf uppáskrifuð en 9% (208) sögðu svo vera. Strákar voru rúmlega helmingi líklegri til að hafa fengið örvandi lyf uppáskrifuð en stúlkur. Tæplega 18% unglinganna í könnuninni kvaðst hafa dreift lyfjunum sínum til annarra með einhverjum hætti. Þeir unglingar eru einnig margfalt líklegri til að sýna af sér annars konar áhættuhegðun. Umræða: Lyfjaflakk örvandi lyfja á meðal 10. bekkinga á Íslandi er algengt miðað við erlendar rannsóknir þar sem hlutfallið er nær 5-10%. Á sama tíma sýna niðurstöðurnar fram á mikilvægi þess að vandað sé til verka hvað varðar aðbúnað og umgjörð slíkar notkunar því til mikils er að vinna, bæði fyrir barnið sjálft og þá sem komast á ólöglegan hátt yfir lyfin og neyta þeirra.Introduction: ADHD is a neurodevelopmental disorder that usually surfaces before seven years of age. Stimulants are commonly used medications for the treatment of this disorder in Iceland, but they carry with them a significant risk of both abuse and diversion – i.e. when it is used by an individual other than it was prescribed for by a physician. The purpose of this study was to estimate the prevalence of diversion amongst Icelandic adolescents. Material and methods: This study is based on data collected in the Icelandic portion of the European School Survey Project on Alcohol and Other Drugs (ESPAD) focused on the drug and alcohol use of 10th graders in Europe. Results: Of the 2,306 students that participated in the study 91% (2,098) claimed they had never been prescribed stimulant medications while 9% (208) claimed they had. Boys were twice as likely to get a stimulant prescription compared to girls. Almost 18% of the participants that had been prescribed simulants said they had at some point in time diverted their stimulant medication. Conclusion: The diversion of stimulants by 10th graders in Iceland is quite common compared to studies from other countries where the prevalence is closer to 5-10%. These findings demonstrate the importance of carefully overseeing stimulant use of adolescents, for the benefit of both those who divert as well as those diverted to

Logarithmic Growth of Dikes From a Depressurizing Magma Chamber

Dike propagation is an intrinsically multiphase problem, where deformation and fluid flow are intricately coupled in a fracture process. Here we perform the first fully coupled simulations of dike propagation in two dimensions, accounting for depressurization of a circular magma chamber, dynamic fluid flow, fracture formation, and elastic deformation. Despite the complexity of the governing equations, we observe that the lengthening is well explained by a simple model a(t) = c₁ log(1 + t/c₂), where is the dike length, is time, and c₁ and c₂ are constants. We compare the model to seismic data from eight dikes in Iceland and Ethiopia, and, in spite of the assumption of plane strain, we find good agreement between the data and the model. In addition, we derive an approximate model for the depressurization of the chamber with the dike length. These models may help forecast the growth of lateral dikes and magma chamber depressurization

Translation and cross-cultural adaptation of the European Health Literacy Survey Questionnaire, HLS-EU-Q16: The Icelandic version

BACKGROUND: Health literacy (HL) is defined as the knowledge and competences of people to meet the complex demands of health in modern society. It is an important factor in ensuring positive health outcomes, yet Iceland is one of many countries with limited knowledge of HL and no valid HL measurement. The aim of this study was to translate the European Health Literacy Survey Questionnaire- short version (HLS-EU-Q16) into Icelandic, adapt the version, explore its psychometric properties and establish preliminary norms. METHODS: The HLS-EU-Q16 translation model included three steps: 1) translation-back-translation of HLS-EU-Q16 including specialists' review (n = 6); 2) cognitive interviewing of lay people (n = 17); and 3) psychometric analysis with survey participants. The HLS-EU-Q16 includes 16 items, with scores ranges from zero (low/no HL) to 16 (high HL). Statistics included were descriptive, internal consistency measured by Cronbach's α, exploratory factor analysis, and multivariate linear regression. RESULTS: After the translation and cognitive interviewing, 11 of the HLS-EU-Q16 items were reworded to adapt the instrument to Icelandic culture while maintaining their conceptual objectives. Survey participants were 251. Internal consistency of the translated and adapted instrument was α = .88. Four factors with eigenvalues > 1.0 explained 62.6% of variance. Principal component analysis with Oblimin rotation presented four latent constructs, "Processing and Using Information from the Doctor" (4 items, α = .77), "Processing and Using Information from the Family and Media" (4 items, α = .85), "Processing Information in Connection to Healthy Lifestyle" (5 items, α = .76), and "Finding Information about Health Problems/Illnesses" (3 items, α = .73). Lower self-rated health was an independent predictor of lower HL (β = -.484, p = .008). Preliminary norms for HL ranged from five to 16 (M 13.7, SD ± 2.6) with 72.5% with sufficient HL (score 13-16), 22% with problematic HL (score 9-12) and 5.5% with inadequate HL (score 0-8). CONCLUSIONS: The Icelandic version of HLS-EU-Q16 is psychometrically sound, with reasonably clear factor structure, and comparable to the original model. This opens possibilities to study HL in Iceland and compare the results internationally. The translation model introduced might be helpful for other countries where information on HL is missing based on lack of validated tools.Háskólinn á Akureyri (IS) research fundPeer Reviewe

Forecasting deflation, intrusion and eruption at inflating volcanoes

A principal goal of volcanology is to successfully forecast the start of volcanic eruptions. This paper introduces a general forecasting method, which relies on a stream of monitoring data and a statistical description of a given threshold criterion for an eruption to start. Specifically we investigate the timing of intrusive and eruptive events at inflating volcanoes. The gradual inflation of the ground surface is a well known phenomenon at many volcanoes and is attributable to pressurised magma accumulating within a shallow chamber. Inflation usually culminates in a rapid deflation event caused by magma escaping from the chamber to produce a shallow intrusion and, in some cases, a volcanic eruption. We show that the ground elevation during 15 inflation periods at Krafla volcano, Iceland, increased with time towards a limiting value by following a decaying exponential with characteristic timescale τ . The available data for Krafla, Kilauea and Mauna Loa volcanoes show that the duration of inflation (t∗) is approximately equal to τ . The distribution of t∗/τ values follows a log-logistic distribution in which the central 60% of the data lie between 0.99 < t∗/τ < 1.76. Therefore, if τ can be constrained during an on-going inflation period, then the cumulative distribution function of t∗/τ values calibrated from other inflation periods allows the probability of a deflation event starting during a specified time interval to be estimated. The time window in which there is a specified probability of deflation starting can also be forecast, and forecasts can be updated after each new deformation measurement. The method provides stronger forecasts than one based on the distribution of repose times alone and is transferable to other types of monitoring data and/or other patterns of pre-eruptive unrest

Seismic Amplitude Ratio Analysis of the 2014–2015 Bár ∂arbunga-Holuhraun Dike Propagation and Eruption

Magma is transported in brittle rock through dikes and sills. This movement may be accompanied by the release of seismic energy that can be tracked from the Earth’s surface. Locating dikes and deciphering their dynamics is therefore of prime importance in understanding and potentially forecasting volcanic eruptions. The Seismic Amplitude Ratio Analysis (SARA) method aims to track melt propagation using the amplitudes recorded across a seismic network without picking the arrival times of individual earthquake phases. This study validates this methodology by comparing SARA locations (filtered between 2- 16 Hz) with the earthquake locations (same frequency band) recorded during the 2014-15 Bárðarbunga-Holuhraun dike intrusion and eruption in Iceland. Integrating both approaches also provides the opportunity to investigate the spatio-temporal characteristics of magma migration during the dike intrusion and ensuing eruption. During the intrusion SARA locations correspond remarkably well to the locations of earthquakes. Several exceptions are however observed. [1] A low-frequency signal was possibly associated with a subglacial eruption on 23 August. [2] A systematic retreat of the seismicity was also observed to the back of each active segment during stalled phases and was associated with a larger spatial extent of the seismic energy source. This behavior may be controlled by the dike’s shape and/or by dike inflation. [3] During the eruption SARA locations consistently focused at the eruptive site. [4] Tremor-rich signal close to ice cauldrons occurred on 3 September. This study demonstrates the power of the SARA methodology, provided robust site amplification, Quality Factors and seismic velocities are available

Evolution of deformation and stress changes during the caldera collapse and dyking at Bárdarbunga, 2014–2015: Implication for triggering of seismicity at nearby Tungnafellsjökull volcano

Stress transfer associated with an earthquake, which may result in the seismic triggering of aftershocks (earthquake–earthquake interactions) and/or increased volcanic activity (earthquake–volcano interactions), is a well-documented phenomenon. However limited studies have been undertaken concerning volcanic triggering of activity at neighbouring volcanoes (volcano–volcano interactions). Here we present new deformation and stress modelling results utilising a wealth of diverse geodetic observations acquired during the 2014–2015 unrest and eruption within the Bárdarbunga volcanic system. These comprise a combination of InSAR, GPS, LiDAR, radar profiling and optical satellite measurements. We find a strong correlation between the locations of increased seismicity at nearby Tungnafellsjökull volcano and regions of increased tensile and Coulomb stress changes. Our results suggest that stress transfer during this major event has resulted in earthquake triggering at the neighbouring Tungnafellsjökull volcano by unclamping faults within the associated fissure swarm. This work has immediate application to volcano monitoring; to distinguish the difference between stress transfer and new intrusive activity