Liquefaction Assessment of a Loose Silty Sand Site in the 2008 Mw 6.3 Ölfus Earthquake

• Main Authors: Fattahi, Seyed Javad, Olafsdottir, Elin Asta, Erlingsson, Sigurdur, Bessason, Bjarni, Rupakhety, Rajesh
• Other Authors: Umhverfis- og byggingarverkfræðideild (HÍ), Faculty of Civil and Environmental Engineering (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland
• Format: Conference Object
• Language: English
• Published: Conspress 2022
• Subjects: Liquefaction hazard; Seismic Zones; Equivalent-linear site response analysis; Jarðskjálftaverkfræði; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/3826

Seismicity in Iceland is related to the Mid-Atlantic plate boundary and primarily consolidated in two complex fracture zones. Liquefaction was observed after the Mw 6.3 Ölfus earthquake in 2008 at the site Arnarbaeli. The site consists of a thick silty sand stratum on the banks of the estuary of the river Ölfusa, and it is located less than 10 km from the earthquake epicentre. Based on nearby time history registrations, the estimated acceleration at the site was 0.6 - 0.7g. Using a simplified method, the safety factor against liquefaction based on the equivalent linear (EL) approach has been estimated. The analysis is built on in-situ field test data (i.e., MASW, and SPT). The analysis reveals the liquefaction depth, 4.4 m. It is shown that not only the current procedure is capable of predicting the occurrence of liquefaction, but also the safety factor which is in good agreement with the observed surface evidence of liquefaction at the site. This work was supported by the Icelandic Research Fund (Rannis), Grants number: 206793-052 and 218149-051. Peer Reviewed