The role of site effects on elevated seismic demands and corollary structural damage during the October 30, 2020, M7.0 Samos Island (Aegean Sea) Earthquake

Altun, Selim
Çetin, Kemal Önder
Unutmaz, Berna
Akgün, Mustafa
Klimis, Nikolaos
Ziotopoulou, Katerina
Askan Gündoğan, Ayşegül
Ilgaç, Makbule
Can, Gizem
Çakır, Elife
Al-Suhaily, Ahmed
Söylemez, Berkan
Elsaid, Alaa
Zarzour, Moutasem
Stewart, Jonathan
Mylonakis, George
On October 30, 2020 14:51 (UTC), a moment magnitude (M) 7.0 (USGS, EMSC) earthquake occurred in the Aegean Sea. This paper presents the reconnaissance findings regarding the site effects on recorded strong ground motion intensities and duration, along with the resulting induced-structural damage in Izmir Bay and Samos Island, respectively. In all rock records, relatively high intensity long period rock spectral accelerations were observed in the mid to long period range of 0.5-1.5 s, which are attributed to the source, more specifically, to the slower rupture-mechanism of the event. These rich spectral intensities were further amplified by soil site effects and soil-superstructure resonance, leading to two to six times amplified overall responses and prolonged seismic shaking durations, more pronounced in Bayrakli and other Izmir Bay sites in Turkey. However, these amplified and prolonged excitations are still below design basis earthquake levels, which addresses the lack of proper structural design and construction deficiencies, as the underlying causes for the collapse to heavy damage performance of 795 buildings. On the other hand, although located only about 10 km from the rupture (22 km from the epicenter) and within the near fault zone, the town of Vathy on Samos Island (Greece) was rather lightly affected by the earthquake, with relatively few collapsed or heavily damaged buildings, partially attributed to the low height/low weight of structures in the area. However, a concentration of damage in low-rise buildings in Ano Vathy hill is considered indicative of a combination of coupled valley and topography effects on the strong motion. This event once again addressed the need to develop region-specific zonation and provisions, when more general code practices are proven to be inadequate to assess these extreme site effects.


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The Samos Island (Aegean Sea) M7.0 earthquake: analysis and engineering implications of strong motion data
Roumelioti, Zafeiria; Askan Gündoğan, Ayşegül; Sotiriadis, Dimitris; Gülerce, Zeynep; Melis, Nikolaos S.; Altindal, Abdullah; Akbaş, Burak; Sopaci, Eyüp; Karimzadeh, Shaghayegh; Kalogeras, Ioannis; Theodoulidis, Nikolaos; Konstantinidou, Kiriaki; Kale, Özkan; Margaris, Basil; Özacar, Atilla Arda (2021-01-01)
We present a dataset of 77 strong ground motion records within 200 km epicentral distance from the 30 October 2020, M7.0 Samos Island (Aegean Sea) earthquake, which affected Greece and Turkey. Accelerograms from National Networks of both countries have been merged into a single dataset, including metadata that have been uniformly derived using a common preliminary source model. Initial findings from the analysis and comparative examination of acceleration time histories, Fourier amplitude spectra and 5%-dam...
Reconnaissance of 2020 M 7.0 Samos Island (Aegean Sea) earthquake
Çetin, Kemal Önder; Sextos, Anastasios; Stewart, Jonathan P. (2021-08-01)
The Samos Island (Aegean Sea) Earthquake occurred on 30 October 2020. It produced a tsunami that impacted coastal communities, ground shaking that was locally amplified in some areas and that led to collapse of structures with 118 fatalities in both Greece and Turkey, and wide-ranging geotechnical effects including rockfalls, landsliding, and liquefaction. As a result of the global COVID-19 pandemic, the reconnaissance of this event did not involve the deployment of international teams, as would be typical ...
Citation Formats
S. Altun et al., “The role of site effects on elevated seismic demands and corollary structural damage during the October 30, 2020, M7.0 Samos Island (Aegean Sea) Earthquake,” BULLETIN OF EARTHQUAKE ENGINEERING, pp. 0–0, 2021, Accessed: 00, 2021. [Online]. Available: