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The Geldingadalir and Meradalir eruptions at Mt. Fagradalsfjall in the Reykjanes Peninsula on 19 March 2021 and 3 August 2022, respectively, were preceded by intense volcano-tectonic swarms. Eight earthquakes with M ≥ 5 were recorded by the Icelandic Strong Motion Network. We present an overview of the seismicity in Fagradalsfjall, and salient features of the strong ground motion caused by the swarms in the epicentral area. The largest recorded horizontal Peak Ground Acceleration (PGA) was ~ 0.45g at Grindavík, which is the strongest PGA recorded in Iceland since the MW6.3 2008 Ölfus Earthquake. Recorded waveforms show a rich long-period energy content, with a burst of higher frequencies at the beginning of shaking. This leads to larger response spectral accelerations at long periods that those from typical shallow crustal earthquakes. Moreover, an empirical mixed-effects ground motion model for PGA was calibrated based on the available recordings. The attenuation rate of PGA from this model is similar to that introduced by Lanzano and Luzi (2020) which is based on data from volcanic events in Italy, but the magnitude scaling of our model is much lower. The overall results indicate that scaling and attenuation of ground motion from volcanic events and purely tectonic earthquakes in Iceland are likely very different. This is an important observation because seismic hazard in parts of the Reykjavik area and of the central highlands, where important hydroelectric power plants are located, could potentially be dominated by events of volcanic origin. Therefore, it is important to take these observations into account for seismic hazard and risk assessment in Iceland.

This deliverable reports an exhaustive state-of-the-art compilation of the most representative seismic fragility and loss estimation models for the buildings and infrastructure components in the testbeds (TBs in the following) of the TURNkey project, which are:TB1-Bucharest (Romania), TB2-Pyrenees (France), TB3-Hveragerði (Southern Iceland) and Húsavík (Northern Iceland), TB4-Patras and Aegio area (Greece), TB5-Port of Gioia Tauro (Italy), and TB6- Groningen (Netherlands).This activity is included within the Work Package 4, aimed at developing and harmonizing seismic physical vulnerability and loss estimation models for structures and infrastructure components within a rapid loss prediction framework. Within a broader context, it may be stated that the contents of this deliverable may also be extrapolated as a useful synthesis of the structural vulnerability standing for the entire European territory. In the chapter 2 of the document,adetailed list of the fragility and loss estimation models adopted for building taxonomies and infrastructure components is tabulated together with their associated publication/reference and a brief description of the corresponding work. Then, futher important information is syntesized in terms of type, structural typology, intensity measure, damage scale, and the region of applicability referring to each individual fragility/loss model under consideration. In chapter 3, in-depth information and discussion of the vulnerability and loss estimation models presented in Chapter 2 are provided for each TB.Furthermore, background exposure information is also provided. Finally, chapter 4 presents the conclusive summary of the Deliverable.

This report details the procedures that have been applied, developed or improved in Task 4.5 for the rapid estimation of damages and losses after an earthquake event. The report revolves around several actions and technical results, which are organized as follows: • Section 3 summarizes the state-of-the-art of current rapid response algorithms and systems, based on a review by Guérin-Marthe et al. (2021). The SELENA and Armargedom software, coupled with shake-map estimates from WP3, are put forward as one of the technical solutions to be implemented in the TURNkey platform. • Section 4 conducts a benchmark study of two damage estimation methods, namely SELENA (Molina et al., 2010), using fragility functions, and Armagedom (Sedan et al., 2013), using semi-empirical vulnerability indices. Both methods are applied on two case-study areas (Luchon area in TB-2 and Alicante area) and the damage distributions are compared. • Section 5 investigates the impact of various factors (resolution of soil amplification maps and building exposure datasets, influence of ground-motion variability) on the accuracy of the damage estimates when applying earthquake scenarios over built areas. Two case studies are considered, namely the Luchon area (TB-2) and the town of Hveragerði (TB3). • Section 6 introduces a probabilistic framework for near real-time seismic damage assessment that exploits heterogeneous sources of information about the seismic input and the structural response to the earthquake. The value of information provided by various combinations of observations and measurements is quantified. The approach is applied to an arbitrary roadway bridge near Patras (TB-4). • Section 7 introduces a sampling-based Bayesian updating method in order to refine damage and loss estimates from field observations. The method is applicable to large real-world systems, such as extended built areas or real-world infrastructure systems. It is applied to the Luchon area (TB-2), where the damage distribution of common buildings and the connectivity loss of the road network system are estimated in a rapid response context. The Bayesian approach for the updating of damage and loss estimated has been implemented in a R/Matlab code, which is briefly described in the companion Deliverable D4.9.

As part of the development of a European Seismic Risk Model 2020 (ESRM20), the spatial and temporal evolution of seismic design across Europe has been studied in order to better classify reinforced concrete buildings (which represent more than 30% of the approximately 145million residential, commercial and industrial buildings in Europe) and map them to vulnerability models based on simulated seismic design. This paper summarises the model that has been developed to assign the years when different seismic design levels (low code, moderate code and high code) were introduced in a number of European countries and the associated lateral forces that were specified spatially within each country for the low and moderate codes for typical reinforced concrete mid-rise buildings. This process has led to an improved understanding of how design regulations evolved across Europe and how this has impacted the vulnerability of the European residential building stock. The model estimates that ~ 60% of the reinforced concrete buildings in Europe have been seismically designed, and of those buildings ~ 60% have been designed to low code, ~ 25% to moderate code and 15% to high code. This seismic design model aims at being a dynamic source of information that will be continuously updated with additional feedback from local experts and datasets. To this end, all of the data has been made openly available as shapefiles on a GitLab repository.

A comprehensive catalogue of historical earthquakes, with accurate epicentres and harmonised magnitudes is a crucial resource for seismic hazard mapping. Here we update and combine catalogues from several sources to compile a catalogue of earthquakes in and near Iceland, in the years 1900–2019. In particular the epicentres are based on local information, whereas the magnitudes are based on teleseismic observations, primarily from international online catalogues. The most reliable epicentre information comes from the catalogue of the Icelandic Meteorological Office, but this is complemented with information from several technical reports, scientific publications, and newspaper articles. The catalogue contains 1281 moment magnitude (Mw) ≥4 events, and the estimated completeness magnitude is Mw 5.5 in the first years, going down to Mw 4.5 for recent years. The largest magnitude is Mw 7.0. Such merging of local data and teleseismic catalogues has not been done before for Icelandic earthquakes, and the result is an earthquake map with much more accurate locations than earlier maps. The catalogue also lists 5640 additional earthquakes on the Mid-Atlantic Ridge, north of 43∘, with both epicentres and magnitudes determined teleseismically. When moment magnitudes are not available, proxy Mw values are computed using χ2 regression, normally on the surface-wave magnitude but exceptionally on the body-wave magnitude. Magnitudes of Mw≥4.5 have associated uncertainty estimates. The actual combined seismic moment released in the Icelandic earthquakes is found to be consistent with the moment estimated using a simple plate motion model, indicating that the seismic activity of the catalogue period might be typical of any 120-year time span. The catalogue is named ICEL-NMAR, and it is available online at http://data.mendeley.com (last access: 19 July 2021).

As buildings become more resilient against structural damage the cost of non-structural damage and their consequences becomes proportionally higher, giving non-structural damage greater importance in earthquake risk reduction. Providing residents with detailed guidance on how to evaluate their risk regarding non-structural earthquake damage, and what mitigation and preparedness options they have, can increase both home and societal earthquake resiliency. Earthquake damage data from destructive earthquakes in south Iceland in 2000 and 2008 were used to develop simple but detailed twelve-step risk-management guidelines for residents. The guidelines are based on a set of disaster-related objectives. A standard loss estimation study was used to develop guidelines for the fixed non-structural elements and photographs from inside homes that had sustained significant non-structural damage were used to develop guidelines for loose items. Virtually every item in the studied homes was considered to understand its importance and its relevance to the function of a home. Information in terms of financial, functional and emotional value were used in the guidelines to help residents decide which mitigation options to take. The photos provided valuable information by placing each item in context with its surroundings, for example, to understand the possibility of motion and consequences to other items. The proposed approach, although based on observations from residential buildings, is useful for facilities that have sensitive operations, such as offices, industrial facilities, hospitals and government services. As societies become more complex and reliant on non-structural elements, systematic and thorough studies such as the one outlined herein become an increasingly critical part of sound earthquake risk management.

Understanding damage to non-structural elements, identifying sources of critical issues, and how damage affects the functionality of facilities are all critical aspects for developing general recommendations concerning disaster risk management. In the present paper a review of non-structural damage caused by recent earthquakes was performed in several localities exposed to seismic hazard such as Mt. Etna in Italy, Lisbon and Azores islands in Portugal and southern Lowland in Iceland. This was needed in order to derive the most common non-structural damage framed into the local situation, which in turn is a basic requirement for a well tailored communication campaign. The observed damage to non-structural elements as derived in this study led to the conclusion that the most commonly damaged elements are partition walls, ceiling systems, non-structural vaults, chimneys, building contents and storage racks. Analyses proved that substantive efforts are needed worldwide to improve techniques for reducing damage to non-structural elements. Non-structural mitigation represents a major opportunity for immediate low-cost action to reduce the impacts of earthquakes at home, school and workplaces. Research results within the KnowRISK EU project was the reference ground upon which a wide range of tools for multi-stakeholders (students, business and citizens) to improve seismic performance of non-structural elements and reducing the associated economic losses, loss of functionality, and potential threats to life safety was designed.

Publisher's version (útgefin grein), In June 2000 two shallow, strike slip, Mw6.5 earthquakes occurred in the middle of the largest agricultural region in Iceland. The epicentres were close to small towns and villages and almost 5000 residential buildings were affected. A great deal of damage occurred but no residential buildings collapsed and there was no loss of life. Insurance against natural disasters is compulsory for all buildings in Iceland and they are all registered in a comprehensive official property database. Therefore, to fulfil insurance claims, a field survey was carried out after the two earthquakes where repair cost was estimated for every damaged building. By combing the loss data with the property database it was possible to establish a complete loss database, where all residential buildings in the affected area were included, both buildings with loss as well as buildings with no-loss. The main aim of the study was to fit a statistical vulnerability model to the data. Due to the high proportion of no-loss buildings in the database (~84%) a new and novel vulnerability model was used based on a zero-inflated beta regression model. The model was fitted to the three main building typologies in the affected region, i.e. low-rise structural wall RC, timber, and masonry buildings. The proposed model can be used to predict the mean and desired prediction limits of the losses for a given intensity level as well as to create fragility functions. All the typologies showed outstanding performance in the two destructive earthquakes, which is important to report, model and learn from., The authors thank the Natural Catastrophe Insurance of Iceland for placing the earthquake damage database and other relevant information at their disposal, and the University of Iceland Research Fund for financial support (Grant no. RSJ-2017 ).

Publisher's version (útgefin grein), In June 2000, two Mw6.5 earthquakes occurred within a 4-day interval in the largest agricultural region of Iceland causing substantial damage and no loss of life. The distance between the earthquake epicentres and the fault rupture was approximately 15 km. Nearly 5000 low-rise residential buildings were affected, some of which were located between the faults and exposed to strong ground motion from both events. The post-earthquakes damage and repair costs for every residential building in the epicentral region were assessed for insurance purposes. The database is detailed and complete for the whole region and represents one of the best quality post-earthquake vulnerability datasets used for seismic loss estimation. Nonetheless, the construction of vulnerability curves from this database is hampered by the fact that the loss values represent the cumulative damage from two sequential earthquakes in some areas, and single earthquakes in others. A novel methodology based on beta regression is proposed here in order to define the geographical limits on areas where buildings sustained cumulative damage and predict the seismic losses for future sequence of events in each area. The results show that the average building loss in areas affected by a single event is below 10% of the building replacement value, whilst this increases to an average of 25% in areas affected by the two earthquakes. The proposed methodology can be used to empirically assess the vulnerability in other areas which experienced sequence of events such as Emilia-Romagna (Italy) in 2012., The authors wish to offer their thanks to the Icelandic Catastrophe Insurance for placing the earthquake loss database and other relevant information at their disposal, and University of Iceland for a research Grant. Ioanna Ioannou and Tiziana Rossetto’s contribution to this study was Funded by the HORIZON2020 Project ‘IMPROVER’ (Grant Number: 653390). Ioannis Kosmidis was supported by The Alan Turing Institute under the EPSRC grant EP/N510129/1 (Turing award number TU/B/000082).

Publisher's version (útgefin grein), Knowledge about the plastic behavior of reinforcement steel bars in reinforced concrete (RC) structures is important, especially for seismic design. This paper presents the results of experimental tests where the main aim was to map the plastic deformations of long ribbed reinforcement bars, both in the axial and lateral directions, in order to provide useful information about the behavior of reinforcement bars inside concrete. The study showed that the digital image correlation (DIC) technique is very suitable for this kind of tests. The uniaxial stress–strain curves for side‐by‐side and different gauge lengths (1d, 3d, 5d, 10d) were identical all the way to the max stress, but after that the segment including the neck dominated the strain development. The Poisson's ratio increased rapidly during the yielding phase to 0.44–0.49 and was constant all the way to rupture. The location of the neck could be predicted at the end of the yielding phase., This work was supported by a doctoral grant from the Eimskip University Fund of the University of Iceland, by the University of Iceland Research Fund, and by the Ludvigs Storr Trust Fund.

Publisher's version (útgefin grein), Multichannel analysis of surface waves (MASW) is a seismic exploration method for determination of near-surface shear wave velocity profiles based on analysis of horizontally travelling Rayleigh waves. This paper aims to propose a methodology and recommendations for combining dispersion data from several multichannel records. The dispersion curves are added up within logarithmically spaced wavelength intervals and the uncertainty of the mean phase velocity estimates is evaluated by using classical statistics and the bootstrap. The results indicate that combining multiple dispersion curves, which have been gathered by receiver spreads of different lengths (but with the same midpoint), can increase the investigation depth of the survey, improve its resolution at shallow depth and overall improve the reliability of the results as compared to the use of a single record. Moreover, the uncertainty of the combined mean dispersion curve can be determined and further used to present the shear wave velocity profile with upper and lower boundaries., This work was supported by the University of Iceland Research Fund [Grant no. 73077]; the Icelandic Road and Coastal Administration [Grant no. 1800-373]; and the Energy Research Fund of the National Power Company of Iceland [Grant no. NYR-18-2017].

In June 2000 two Mw6.5 earthquakes occurred in South Iceland and in May 2008 an Mw6.3 quake struck in the same area. High PGAs (>0.6 g) were registered in all cases. The epicentres were located in an agriculture region and close to small towns and villages. Nearly 9500 residential buildings were affected. A great deal of damage occurred but there was no loss of life. Insurance against natural disasters is obligatory for all buildings in Iceland and they are all registered in a comprehensive property database. Therefore, after each quake a field survey was carried out where damage and repair costs were estimated for every structure. Most of the damage was observed in the near-fault area (0–10 km) but at longer distances it was significantly less. The damage in the two Mw6.5 events was considerably greater than in the Mw6.3 event. In all the events a high proportion of buildings were undamaged, even in the near-fault area. The main damage was non-structural, in interior walls and flooring. New buildings built after implementation of seismic codes performed better than those built pre-code.

Since 1983, 15 Icelandic bridges have been base isolated for seismic protection. Lead-rubber bearings have been used in all cases. Nine of these bridges are located in the South Iceland Lowland, which is an active seismic zone where earthquakes of magnitude seven can be expected. In June 2000 two Mw6.5 earthquakes struck in the area and in May 2008 a Mw6.3 event hit the area again. Four of the base isolated bridges were located in the near-fault area of these earthquakes with a fault-to-site distance of less than 15 km, and most likely three of them were subjected to strong low-frequency near-fault velocity pulses. None of the bridges collapsed or were severely damaged and all of them were open for traffic immediately after these events. Post-earthquake response analysis has indicated that the base isolation was important for the performance of the bridges.

Multichannel Analysis of Surface Waves (MASW) is a seismic exploration method to evaluate shear wave velocity profiles of near-surface materials. MASW was applied at seven locations in or close to the South Iceland Seismic Zone, providing shear wave velocity profiles for the top-most 15–25 m. The profiles were utilized for seismic soil classification according to Eurocode 8. The results indicated that the sites that are characterized by sandy glaciofluvial, littoral or alluvial sediments fall into category C and the sites where the deposits are cemented to some degree belong to category B. Furthermore, the MASW measurements were used to evaluate the liquefaction potential at a site where liquefaction sand boils were observed during an Mw6.3 earthquake occurring in May 2008. The simplified procedure of assessing cyclic stress ratio to normalized shear wave velocity revealed that liquefaction had occurred down to 3–4 m depth, which is consistent with observations on site.

Multichannel analysis of surface waves (MASW) is a fast, low-cost, and environmentally friendly technique to estimate shear wave velocity profiles of soil sites. This paper introduces a new open-source software, MASWaves, for processing and analysing multichannel surface wave records using the MASW method. The software consists of two main parts: a dispersion analysis tool (MASWaves Dispersion) and an inversion analysis tool (MASWaves Inversion). The performance of the dispersion analysis tool is validated by comparison with results obtained by the Geopsy software package. Verification of the inversion analysis tool is carried out by comparison with results obtained by the software WinSASW and theoretical dispersion curves presented in the literature. Results of MASW field tests conducted at three sites in south Iceland are presented to demonstrate the performance and robustness of the new software. The soils at the three test sites ranged from loose sand to cemented silty sand. In addition, at one site, the results of existing spectral analysis of surface waves (SASW) measurements were compared with the results obtained by MASWaves., The project has been supported financially by grants from the University of Iceland Research Fund, the Icelandic Road and Coastal Administration, and the Energy Research Fund of the National Power Company of Iceland.

Snow is a highly nonlinear viscoelastic material characterized by a complex microstructure. This paper presents a constitutive model for snow that is based on the axial and inelastic microstructural deformations of the ice lattice. It determines the average microstructural stress in the grain necks and then applies a strain-rate and temperature dependent viscosity law of pure ice to describe the deformation of the solid ice lattice. The law is valid for strain-rates between 0.0000001/s and 0.00001/s. The constitutive model is validated using mechanical tests performed with a specially designed deformation controlled triaxial apparatus. Stereological thin sections were taken of the experimental samples to determine the grain and bond size as well as coordination number. A final step attempts to apply the microstructural theory to determine a microstructure-based elasticity law, but without success. It is concluded that the elastic and viscous behavior of snow are governed by different microstructural deformation processes.

In May 2008 a shallow Mw6.3 earthquake struck South Iceland with an epicentre close to two small towns. Nearly 5000 low-rise residential buildings were affected. The recorded maximum PGA was 0.88 g. A great deal of damage occurred, but there was no loss of life. In Iceland all buildings are registered in a detailed official database and insurance against natural disasters is obligatory. As the repair costs for every affected building had to be assessed for insurance purposes this provided an unusual opportunity to review structural performance across the whole population of buildings in the affected area. The estimated repair cost was classified in a number of subcategories covering structural and non-structural damage for five different residential building typologies. Study of these buildings showed that non-structural damage dominated the overall damage. The main monetary damage was cosmetic damage of partition walls and flooring. The structural systems performed quite well and no buildings collapsed.

The seismicity in Iceland is related to the Mid-Atlantic plate boundary which crosses the country from north to south. Since 1700, there have been 25 earthquakes of magnitude six or greater in the two major seismic zones in Iceland. For many of the historical earthquakes (older than 100 years), detailed written descriptions are available that describe the damage from farm to farm. For the most recent earthquakes, like the two south Iceland earthquakes of June 2000 and the south Iceland earthquake of May 2008, comprehensive building-by-building loss data exist. The loss data in these cases are split into a number of subcategories of structural and non structural damage. The building stock in south Iceland has changed significantly from 1700 to the present. For ages, vulnerable turf and stone houses dominated, but in the twentieth century, concrete buildings and timber buildings took over. Seismic codes were implemented in 1976 and have gradually improved the seismic capacity of present building stock. In this book chapter, an overview of the seismic performance of old and new Icelandic buildings is given. Observed and reported damage caused by three earthquake sequences and a single event are discussed; first, the damage caused by two earthquakes in August 1784 in south Iceland; then, by the 1896 earthquake sequence in south Iceland; then, the damage after a single event in 1934 in north Iceland; and finally, the loss data from the 2000 and 2008 earthquakes in south Iceland. The main focus is on the last three events for which most of the data exist.

All buildings in Iceland are registered in an official database that contains detailed information about them, and insurance against natural disasters is obligatory. When a destructive earthquake occurs, all damage is reported, and the repair and replacement cost for every affected building is evaluated. In May 2008, a shallow earthquake of magnitude Mw = 6.3 struck in South Iceland. A great deal of damage occurred, but fortunately, there was no loss of life. The recorded maximum PGA was 0.88 g. Detailed and complete information of all real estate property and the damage incurred, along with recorded strong-motion data and an area-specific attenuation model, have provided an opportunity to create probabilistic damage curves for the building stock in the affected area. The damage model obtained from the 2008 earthquake was tested and verified by using it to back-calculate the damage that occurred in the two South Iceland earthquakes of June 2000 ( Mw = 6.5).

Í júní 2000 urðu tveir jarðskjálftar á Suðurlandi af stærðinni Mw 6,5 og í maí 2008 varð einn til viðbótar af stærðinni Mw6,3 í Ölfusi. Útgildi hröðunar var yfir 0,6 g (g er þyngdarhröðun jarðar) í öllum þessum þremur skjálftum. Um 9.500 íbúðarbyggingar eru staðsettar á áhrifasvæði þessara skjálfta. Töluvert tjón varð í skjálftanum, en til allrar hamingju urðu nánast engin slys á fólki og ekkert dauðsfall. Allar byggingar á Íslandi eru skráðar í opinberri fasteignskrá sem inniheldur margvíslegar upplýsingar um þær. Samkvæmt lögum eru allar fasteignir landsmanna tryggðar gegn náttúrvá hjá Viðlagatryggingu Íslands. Til að meta tryggingarbætur eftir skjálftana voru matsmenn fengnir til að skoða skemmdir og áætla viðgerðarkostnað fyrir allar byggingar á svæðinu, þar sem tilkynnt var um tjón. Mesta tjónið reyndist vera nálægt upptökum og þá gjarnan í 0-10 km fjarlægð frá kortlögðum jarðskjálftasprungum. Tjón í fyrri tveimur 6,5 skjálftunum var meira og útbreiddara en í 6,3 skjálftanum. Í öllum þremur var töluvert um byggingar sem sluppu án skemmda. Mesta tjónið reyndist vera útlitstjón á léttum innveggjum og gólfefnum sem og skemmdir á innréttingum. Nýrri byggingar sem hannaðar voru eftir innleiðingu jarðskjálftastaðla stóðu sig að jafnaði betur en eldri byggingar. In June 2000, two Mw6.5 earthquakes occurred in South Iceland and in May 2008 an Mw6.3 quake struck in the same area. High PGAs (>0.6 g) were registered in all three events. The epicentres were located in an agriculture region and close to small towns and villages. In total, nearly 9,500 residential buildings were affected. A great deal of damage occurred but there was no loss of life. Insurance against natural disasters is obligatory for all buildings in Iceland and they are all registered in a comprehensive property database. Therefore, after each earthquake a field survey was carried out where damage and repair costs were estimated for every structure. Most of the damage was observed in the near-fault area (0-10km) but at longer distances it was significantly less. The damage in the two Mw6.5 events was considerably greater than in the Mw6.3 event. In all the events a high proportion of buildings suffered no damage, even in the near-fault area. The main damage was nonstructural, in interior walls and flooring. New buildings built after implementation of seismic codes performed better than those built pre-code.

The South Iceland Lowland is an active seismic zone. In May 2008 a magnitude 6.3 (Mw) earthquake struck the area. The 370-m-long base-isolated Oseyrar Bridge situated close to the epicentre was hit by strong ground motion. Concrete stoppers at the top of all piers were badly smashed and all four wing walls of the abutments were severely damaged. The study showed that it is possible with numerical models to back-calculate the observed damage based on recorded ground motion in the area. The recorded loads were larger than prescribed by Eurocode 8 for the site even though the magnitude and location of the earthquake was as expected. The main reason was a near-fault pulse which is not covered in the code. The pulse dominated the bridge response and is therefore important to consider. Finally, an improved design is presented that could have prevented the damage.

Since 1983, 12 Icelandic bridges have been base isolated for seismic protection. Lead-rubber bearings have been used in all the cases. The Thjorsa River Bridge, built in 1950 and retrofitted with base isolation in 1991, is instrumented by strong-motion accelerometers. The bridge has one 83-m-long main span and two 12-m-long approach spans. Only the main span, a steel arch truss with concrete deck, is base isolated. In June 2000, two major earthquakes of magnitude 6.6 and 6.5 occurred in South Iceland; the epicenter was close to the Thjorsa River Bridge. In the first earthquake, a peak ground acceleration of 0.53 g was recorded at the bridge site, and in the second earthquake, a peak ground acceleration of 0.84 g was recorded. The Thjorsa River Bridge survived the earthquakes without any serious damage and was open for traffic immediately after the earthquakes.

Seismicity and volcanic activity in Iceland are related to the Mid-Atlantic plate boundary that crosses the island. Due to volcanic activity, different sea levels through the ages and glacial drift, the geology in Iceland is quite complex at many sites. In June 2000, two major earthquakes of magnitude 6.6 (Mw) and 6.5 (Mw) occurred in southern Iceland. Ground motion from these main shocks and a number of aftershocks were recorded at the Icelandic strong motion network operated by the University of Iceland. At one of the instrumented sites considerable amplification was recorded on lava-rock overlying alluvial deposits. This site fits poorly in the soil classification systems of most earthquake codes. In this paper the recorded data is analyzed with different methods and the results are compared with the results of a one-dimensional site response analysis. The different methods produce the same characteristic of soil amplification at the site. The findings of this study have important implications for design criteria for sites with similar geology. q 2002 Elsevier Science Ltd. All rights reserved.

The Norwegian Metrology and Accreditation Service (Justervesenet) inaugurated a new facility early in 1997. The facility allows measurements of mass, density, dimension, force, volume, optics, pressure, temperature and electrical quantities. Vibration control is of concern in most of the laboratories. Vibration criteria have been defined by frequency-dependent peak values. Vibrations affecting the laboratories can be classified as originating in either internal or external vibration sources. Internal vibrations are generated by human activity, mechanical systems and equipment inside the building, while external vibration sources represent all sources outside the building. In order to map and estimate the vibration level at the site and inside the new facility, an extensive measurement and analysis programme was carried out. This programme included four main activities, that is, vibration monitoring at the site for 37 days, controlled measurements of vibrations from diverse internal vibration sources, earthquake hazard analysis and, finally, analysis of footstep-induced vibrations. Based on the results from this programme, the principal layout of the building was formulated, and countermeasures were designed to fulfil the vibration criteria specified for the laboratories. The countermeasures were basically threefold, that is, active vibration isolation of the internal sources, constructional joints to cut wave transmission paths and passive vibration isolation of the foundations supporting the sensitive equipment.

Establishment of appropriate vibration criteria is essential when designing vibration-sensitive metrology laboratories. Boundary values that are too severe may lead to unnecessarily high construction costs, whereas limits that are too broad may result in degradation of the performance of measurement equipment. The Norwegian Metrology and Accreditation Service (Justervesenet) inaugurated a new facility early in 1997. The facility will allow measurements of mass, density, dimensional, force, volume, optical, pressure, temperature and electrical quantities. Vibration control is of concern in most of the laboratories. Vibration criteria have been defined in terms of frequency-dependent peak values. In this paper, these criteria are described and the most conservative criterion is compared with other known vibration criteria for standard laboratories and high-technology facilities. The vibration criteria considered have different formulations and cannot be compared directly. They are therefore compared with regard to three different kinds of idealized vibration excitation, that is, transient, harmonic-motion and broad-band noise. The comparison shows that the most conservative Justervesenet vibration criterion is stricter with respect to high-frequency vibrations than are the others, but it is less strict for low-frequency vibrations.

Þann 29. maí 2008 varð jarðskjálfti af stærðinni 6,3 (Mw) í Ölfusi. Upptök skjálftans og tvö misgengi hans voru nálægt nokkrum smábæjum og þéttbýliskjörnum á svæðinu. Hágildi yfirborðshröðunar var skráð 0,88g í Hveragerði sem er aðeins 2–3 km frá meginmisgenginu. Töluvert tjón varð í skjálftanum, en til allra hamingju urðu nánast engin slys á fólki og ekkert dauðsfall. Allar byggingar á Íslandi eru skráðar í opinberri fasteignskrá sem inniheldur margvíslegar upplýsingar um þær. Samkvæmt lögum eru allar fasteignir landsmanna tryggðar gegn náttúrvá hjá Viðlagatryggingu Íslands. Til að meta tryggingarbætur eftir Ölfusskjálftann voru matsmenn fengnir til að skoða skemmdir og áætla viðgerðarkostnað fyrir allar byggingar á svæðinu, þar sem tilkynnt var um tjón. Tjón á hverri fasteign var flokkað í marga fyrirfram skilgreinda undirflokka. Rannsókn á þessum tjónagögnum sýnir að skemmdir á burðarvirki er aðeins lítið hlutfall af heildartjóni, ef miðað er við útgreiddar tryggingabætur. Stærstur hluti bóta fór í að bæta viðgerðakostnað vegna útlitsskaða á veggjum sem þörfnuðust minniháttar sprunguviðgerða og endurmálunar sem og til að bæta skemmdir á gólfefnum eins og parketi og flísum. The South Iceland lowland is an active seismic zone. In May 2008 a shallow Mw6.3 earthquake occurred in the Ölfus region in South Iceland. The epicentre was located in the middle of farmlands and also close to two small towns in the area. The recorded maximum PGA was 0.88g in the town Hveragerði, about 2–3 km from the main fault. A great deal of damage occurred, but fortunately there was no loss of life. All buildings in Iceland are registered in a detailed official database. Insurance against natural disasters is obligatory. After the Ölfus earthquake, damage and repair cost for every affected building was estimated by trained estimators in order to cover the loss incurred for policy holders. The damage data for every property was split into number of subcategories. Analysis of the data showed that damage of structural elements was only a fraction of the total damage, and most of the estimated repair cost was related to cosmetic non-structural surface damage that required replacement of flooring, tiles and paint work.

A semi-empirical model for predicting low frequency vibration that may annoy building occupants in areas with soft ground conditions has been developed and used for the planning of a new high speed railway line in Norway. The model has a statistical formulation, and predicts both expected values and confidence limits for the vibration. The model is based on a large number of vibration measurements in Norway and Sweden. To manage the systematic and unified handling of the measured vibration data needed to develop the model, a database has been defined and established. It is hoped that more institutions could agree on using one common data structure and start data interchange. This would make more data available for continued improvements of empirical prediction models and for validation of numerical vibration simulation codes.

The road along the Óshlíð hillside in the West Fjords region of Iceland is one of the most hazardous roads in Iceland due to avalanches, rockfalls and debris flows. The road has little traffic, but nevertheless traffic accidents caused by the severe conditions at the site are common. A number of avalanche tracks are found on the hillside. In some of these tracks, avalanches occur more frequently than in others. When there is an avalanche threat, avalanches generally flow over many tracks in a short time. Monitoring vibrations in the tracks with the highest avalanche frequency can indicate when avalanches start flowing down the hillside in a snowstorm, and avalanche hazard can then be declared with the specific site indicated. The same methodology can be used for rockfalls and debris flows, which are strongly affected by weather conditions and typically occur in clusters. Based on this knowledge, a research project was initiated in February 1996 with the objective of developing an automatic system based on seismic measurements to detect and analyze avalanches on the Óshlíð hillside and to instantly send a warning to a control station.

Shear wave velocity is a fundamental parameter in soil dynamics and geotechnical earthquake engineering. The Multichannel Analysis of Surface Waves (MASW) method is a relatively new non-invasive technique to evaluate the near-surface shear wave velocity profile by utilizing the dispersive properties of surface waves in a heterogeneous medium. The method is both time and cost efficient and can be applied at a wide variety of soil sites, including locations where conventional invasive techniques are difficult to apply. The main objectives of the project were (i) to develop an open software to acquire, process and analyse MASW field data, (ii) to validate and calibrate field observations by comparison with results obtained by other measurement techniques and alternative software packages, and (iii) to implement and adapt MASW for analysis of the stiffness properties of Icelandic soil sites and man-made fillings. Alongside software development, an effort has been made to develop methods for combining dispersion curves from a number of records gathered at a given site, with the aim of increasing the range in investigated depths, get more reliable results, and assess experimental uncertainties. Furthermore, a simple but effective Monte Carlo-based technique has been developed for use in the MASW inversion analysis. To date, MASW has been applied at over twenty natural locations in Iceland, ranging from sites characterized by peat and loosely compacted sand to cemented soil materials and soft rock. Where available, the results were compared to existing measurements. The method has also been successively applied for analysis of earth dams. In order to benchmark results obtained by the new software, field measurements were carried out at Norway’s National GeoTest Sites. The shear wave velocity profiles obtained by the new software (MASWaves) agreed well with results of existing measurements, thus verifying the performance of the set of data acquisition and analysis tools., Þekking á jarðtæknilegum eiginleikum setlaga og jarðvegsfyllinga, svo sem þykkt og stífni einstakra laga, er mikilvæg í jarðtæknilegri hönnun og jarðtæknilegri jarðskjálftaverkfræði. Fjölnemagreining á yfirborðsbylgjum (MASW) er nýleg aðferð sem byggir á tvístrunareiginleikum yfirborðsbylgna og tengslum milli útbreiðsluhraða þeirra og fjaðureiginleika jarðvegs. Yfirborðsbylgjur eru framkallaðar með höggi á yfirborð jarðar og útbreiðsla þeirra er mæld. Mæligögnin eru, ásamt eðlisfræðilegu reiknilíkani, notuð til að ákvarða skúfbylgjuhraða sem fall af dýpi. MASW mælingar eru hagkvæmar og fljótlegar í framkvæmd og valda ekki raski. Þá hentar MASW vel í grófum jarðvegi þar sem erfitt eða ómögulegt er að þrýsta niður kónískum nemum. Meginmarkmið þessa verkefnis voru að (i) þróa opinn hugbúnað fyrir feltmælingar og úrvinnslu mæligagna, (ii) sannreyna niðurstöður með samanburði við mælingar sem framkvæmdar hafa verið af óháðum rannsakendum og (iii) aðlaga og þróa MASW til mælinga á íslenskum jarðvegi. Samhliða gerð hugbúnaðar hefur verið þróuð aðferðafræði til að flétta saman tvístrunarferla, sem ákvarðaðir hafa verið með endurteknum höggum á yfirborð jarðar, með það fyrir augum að auka könnunardýpi MASW aðferðarinnar, meta gæði mæligagna og áætla óvissu í afleiddum stærðum. Líkan til bakreikninga á skúfbylgjuhraða, sem byggt er á Monte Carlo hermun, hefur einnig verið þróað. Til þessa hafa MASW mælingar verið framkvæmdar á rúmlega tuttugu náttúrlegum stöðum hérlendis, auk þess sem mælingar hafa verið gerðar á jarðstíflum með góðum árangri. Enn fremur voru MASW mælingar framkvæmdar á prófunarstöðum í Noregi þar sem erlendir rannsóknahópar hafa mælt skúfbylgjuhraða með fjölda annarra aðferða. Niðurstöðum mælinga ber mjög vel saman við fyrirliggjandi niðurstöður. Því má álykta að aðferðafræðin og sá hugbúnaður sem hefur verið þróaður (MASWaves) skili áreiðanlegum niðurstöðum.

The rock sliding occurred in the Republic of Kosovo, in February 2017, on the part of motorway under construction. Landslide mass, in the area of 0.9 ha, came down the slope above viaduct piers in construction and pushed on them. The immediate result was the tilting and structural failure of viaduct’s pier. Following the event, extensive soil investigation works were carried out and remediation were proposed. Rock slide happened on mountain section, where terrain is composed of tectonically crushed gneiss rock and weakly bound and unbound deluvial sediments and colluvium masses. Accepted solution included removing damaged piers and construction of new ones, with protection, retaining structures, which would resist sliding mass and protect piers from its influence (Szavits-Nossan, 2009). In designing, 2D geotechnical and 3D structural models were used to predict behaviour of arch shaped retaining structures. Designing was supported with monitoring from site and the works successfully continued.