Strong ground motion from the seismic swarms preceding the 2021 and 2022 volcanic eruptions at Fagradalsfjall, Iceland

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 ~ 0.45 g 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, PGV and PSA was calibrated for rock sites based on the available recordings. The attenuation rate from this model is similar to that introduced by Lanzano and Luzi (Bull Earthq Eng 18(1):57–76, 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 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

Calibration of input parameters in volcanic areas and an enlarged dataset by stochastic finite-fault simulations

The calibration of input parameters is an important task for stochastic finite-fault simulation in volcanic areas, and we manage this in the framework of the European project UPStrat-MaFa. The stochastic simulation method requires the knowledge of fault geometry, source, crust properties of the region, and local site effects. At first, we focused the present study in the pilot test areas: Mt Vesuvius, Campi Flegrei and Mt Etna. Later, we performed two applications for a large magnitude event in the Azores Islands and the South Iceland regions. A general preliminary database of ground-motion records was collected in the test areas, to set up the empirical laws of the ground-motion parameters. The results of the simulations have been compared with observed waveforms and response spectra, to determine the suitability of the parameters used. The results show good agreement between the observed and simulated time histories and response spectra, thus encouraging further efforts towards quantitative high resolution studies on input parameters.Co-financed by the EU - Civil Protection Financial Instrument, in the framework the European project ”Urban disaster Prevention Strategies using MAcroseismic Fields and FAult Sources (Acronym: UPStrat-MAFA, Grant Agreement N. 23031/2011/613486/SUB/A5). http://ec.europa.eu/echo/funding/cp_projects2011_en.htmPublishedLisbon - Portugal4.1. Metodologie sismologiche per l'ingegneria sismicaope

Calibration of input parameters in volcanic areas and an enlarged dataset by stochastic finite-fault simulations

The calibration of input parameters is an important task for stochastic finite-fault simulation in volcanic areas, and we manage this in the framework of the European project UPStrat-MaFa. The stochastic simulation method requires the knowledge of fault geometry, source, crust properties of the region, and local site effects. At first, we focused the present study in the pilot test areas: Mt Vesuvius, Campi Flegrei and Mt Etna. Later, we performed two applications for a large magnitude event in the Azores Islands and the South Iceland regions. A general preliminary database of ground-motion records was collected in the test areas, to set up the empirical laws of the ground-motion parameters. The results of the simulations have been compared with observed waveforms and response spectra, to determine the suitability of the parameters used. The results show good agreement between the observed and simulated time histories and response spectra, thus encouraging further efforts towards quantitative high resolution studies on input parameters

Quantitative seismic risk evaluation and mapping: cases of schools and residential facilities in Lisbon and Algarve

This contribution deals with activities within the framework of an EC-project, entitled "UPStrat-MAFA (Urban prevention strategies using macroseismic and fault sources)", emphasising the inventory, vulnerability and seismic risk of buildings. The cases considered deal with elementary and non-elementary public schools as well as the residential building stock in Lisbon and Algarve in mainland Portugal. A new concept of global disruption measures is introduced and discussed, with the objective of providing a systematic way to quantify earthquake impact in urban areas. This approach provides civil protection, the authorities and local decision makers with a new tool judged to be valuable in prioritizing mitigation measures and responses.Co-financed by the EU - Civil Protection Financial Instrument, in the framework the European project ”Urban disaster Prevention Strategies using MAcroseismic Fields and FAult Sources (Acronym: UPStrat-MAFA, Grant Agreement N. 23031/2011/613486/SUB/A5). http://ec.europa.eu/echo/funding/cp_projects2011_en.htmPublishedLisbon - Portugal4.1. Metodologie sismologiche per l'ingegneria sismicaope

Quantitative seismic risk evaluation and mapping: cases of schools and residential facilities in Lisbon and Algarve

This contribution deals with activities within the framework of an EC-project, entitled "UPStrat-MAFA (Urban prevention strategies using macroseismic and fault sources)", emphasising the inventory, vulnerability and seismic risk of buildings. The cases considered deal with elementary and non-elementary public schools as well as the residential building stock in Lisbon and Algarve in mainland Portugal. A new concept of global disruption measures is introduced and discussed, with the objective of providing a systematic way to quantify earthquake impact in urban areas. This approach provides civil protection, the authorities and local decision makers with a new tool judged to be valuable in prioritizing mitigation measures and responses

TheKnowRISKproject:Tools and strategies for risk communication and learning

Damage of non-structural elements of buildings (i.e. partitions, ceilings, cladding, electrical and mechanical sys- tems and furniture) is known to cause injuries and human losses. Also it has a significant impact on earthquake resilience and is yet being worldwide underestimated. The project KnowRISK (Know your city, Reduce seISmic risK through non-structural elements) is financed by the European Commission to develop prevention measures that may reduce non-structural damage in urban areas. Pilot areas of the project are within the three European participating countries, namely Portugal, Iceland and Italy. They were chosen because they are prone to damage level 2 and 3 (EMS-98, European Macroseismic Scale) that typically affects non-structural elements. We will develop and test a risk communication strategy taking into ac- count the needs of households and schools, putting into practice a portfolio of best practice to reduce the most common non-structural vulnerabilities. Wewilltargetouractionstodifferentsocietalgroups,consideringtheirculturalbackgroundandsocialvulnerabil- ities, and implement a participatory approach that will promote engagement and interaction between the scientific community, practitioners and citizens to foster knowledge on everyone’s own neighborhoods, resilience and vul- nerability. A Practical Guide for citizens will highlight that low-cost actions can be implemented to increase safety of house- holds,meantasbeingtheplaceswherethemostvulnerablesocietalgroups,includingchildrenandelderlypeople, spend much of their time. Since our actions towards communication will include education, we will define tools that allow a clear and direct understanding of elements exposed to risk. Schools will be one of our target societal groups and their central role played at the community level will ensure spreading and strengthening of the communication process. Schools are often located in old or re-adapted build- ings,formerlyusedforotheruses,orwhenthegrowingnumberofstudentsornewneedsrequireadaptingthespace to the necessities, often without taking enough care of safety. Moreover, in urban areas, schools may be hosted in tall buildings where the shaking of moderate-to-low magnitude earthquakes can cause damage level 2 and 3. Students will be involved into looking after their own situation in terms of non-structural vulnerability to promote education and prevention, while increasing resilience in terms of societal capacity to cope with future disasters. The actions will undergo specific effectiveness assessment with ex-ante and ex-post surveys. The results of this assessmentwillallowanevaluationofon-siteriskcommunicationactivities,thecomparabilitybetweenpilot-areas achievements, and an opportunity for learning and guidance for future risk communication.PublishedVienna, Austria3T. Pericolosità sismica e contributo alla definizione del rischioope

The KnowRISK project: Tools and strategies to reduce non-structural damage

The project KnowRISK (Know your city, Reduce seISmic risK through non-structural elements) is financed by the European Commission to develop prevention measures that may reduce non-structural damage in urban areas. Pilot areas of the project are within the three European participating countries, namely Portugal, Iceland and Italy. Non-structural components of a building include all those components that are not part of the structural system, more specifically the architectural, mechanical, electrical, and plumbing systems, as well as furniture, fixtures, equipment, and contents. Windows, partitions, granite veneer, piping, ceilings, air conditioning ducts and equipment, elevators, computer and hospital equipment, file cabinets, and retail merchandise are all examples of nonstructural components that are vulnerable to earthquake damage. We will use the experience gained during past earthquakes, which struck in particular Iceland, Italy and Portugal (Azores). Securing the non-structural elements improves the safety during an earthquake and saves lives. This paper aims at identifying non-structural seismic protection measures in the pilot areas and to develop a portfolio of good practices for the most common and serious non-structural vulnerabilities. This systematic identification and the portfolio will be achieved through a “crossknowledge” strategy based on previous researches, evidence of non-structural damage in past earthquakes. Shake table tests of a group of non-structural elements will be performed. These tests will be filmed and, jointly with portfolio, will serve as didactic supporting tools to be used in workshops with building construction stakeholders and in risk communication activities. A Practical Guide for non-structural risk reduction will be specifically prepared for citizens on the basis of the outputs of the project, taking into account the local culture and needs of each participating countryPublishedVienna3T. Pericolosità sismica e contributo alla definizione del rischiorestricte

Urban Disaster-Prevention Strategies Using Macroseismic Fields and Fault Sources

This contribution presents the general framework of the European project UPStrat-MAFA "Urban disaster Prevention Strategies using MAcroseismic Fields and FAult Sources" and its ongoing activities. A unique probabilistic procedure is being used for seismic hazard evaluation, using both macroseismic fields and characteristics of fault sources for the analysis of data from volcanic and tectonic areas: Mt. Etna, Mt. Vesuvius and Campi Flegrei (Italy), Azores Islands (Portugal), South Iceland (Iceland), Alicante-Murcia (Spain), and mainland and offshore Portugal. An improvement of urban scale vulnerability information on building and network systems (typologies, schools, strategic buildings, lifelines, and others) is proposed in the form of a global Disruption Index, with the objective to provide a systematic way of measuring earthquake impact in urbanized areas considered as complex networks. Disaster prevention strategies are considered based on an education information system, another effective component of the disaster risk reduction given by long-term activities.Co-financed by the EU - Civil Protection Financial Instrument, in the framework the European project ”Urban disaster Prevention Strategies using MAcroseismic Fields and FAult Sources (Acronym: UPStrat-MAFA, Grant Agreement N. 23031/2011/613486/SUB/A5). http://ec.europa.eu/echo/funding/cp_projects2011_en.htmPublishedLisbon - Portugal4.1. Metodologie sismologiche per l'ingegneria sismicaope

Urban Disaster-Prevention Strategies Using Macroseismic Fields and Fault Sources

This contribution presents the general framework of the European project UPStrat-MAFA "Urban disaster Prevention Strategies using MAcroseismic Fields and FAult Sources" and its ongoing activities. A unique probabilistic procedure is being used for seismic hazard evaluation, using both macroseismic fields and characteristics of fault sources for the analysis of data from volcanic and tectonic areas: Mt. Etna, Mt. Vesuvius and Campi Flegrei (Italy), Azores Islands (Portugal), South Iceland (Iceland), Alicante-Murcia (Spain), and mainland and offshore Portugal. An improvement of urban scale vulnerability information on building and network systems (typologies, schools, strategic buildings, lifelines, and others) is proposed in the form of a global Disruption Index, with the objective to provide a systematic way of measuring earthquake impact in urbanized areas considered as complex networks. Disaster prevention strategies are considered based on an education information system, another effective component of the disaster risk reduction given by long-term activities

From seismic input to damage scenario: an example for the pilot area of Mt. Etna volcano (Italy) in the KnowRISK Project

In this paper we present a multidisciplinary approach aimed at assessing seismic risk due to non-structural damage. The study has been carried out in the framework of the European KnowRISK Project and focuses on the pilot area of Mt. Etna volcano (Italy). Both instrumental data and as well as macroseismic observations provide unique opportunities for testing innovative and classical approaches for assessing seismic risk. Starting from the seismic hazard analysis, we first identify a test site (Zafferana) affected by non-structural damage. We produce seismic scenarios based on macroseismic and ground-motion data and finally obtain the relevant risk map using the Italian census data to classify buildings into vulnerability classes and a model to predict damage distribution.PublishedReykjavik, Iceland4T. Sismologia, geofisica e geologia per l'ingegneria sismic