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.


The Assessment of Seismic Site Effects During The 24 January 2020 Elazig-Sivrice Mw: 6.8 Earthquake
Elsaid, Alaa; Çetin, Kemal Önder; Department of Earthquake Studies (2022-2-11)
At 8:55 p.m. local time (17:55 GMT) on January 24, the Sivrice district of Elazig, located on Turkey's second-largest fault system, was struck by a severe earthquake with a magnitude of 6.8 (AFAD) or 6.7 according to USGS. Tragically, the earthquake resulted in severe devastation, including structural damage and fatalities. In order to aid in the mitigation of potential earthquake damage that may occur in the region and to serve as a guide for site-specific seismic design for future earthquakes, the seismic...
Geotechnical reconnaissance findings of the October 30 2020, Mw7.0 Samos Island (Aegean Sea) earthquake
Ziotopoulou, Katerina; et. al. (2022-11-01)
On October 30, 2020 14:51 (UTC), a moment magnitude (Mw) of 7.0 (USGS, EMSC) earthquake occurred in the Aegean Sea north of the island of Samos, Greece. Turkish and Hellenic geotechnical reconnaissance teams were deployed immediately after the event and their findings are documented herein. The predominantly observed failure mechanism was that of earthquake-induced liquefaction and its associated impacts. Such failures are presented and discussed together with a preliminary assessment of the performance of ...
The possibility of tsunami in the Sea of Okhotsk caused by deep-focus earthquakes
Zaytsev, A. I.; Pelinovsky, E. N.; Kurkin, A. A.; Kostenko, I. S.; Yalçıner, Ahmet Cevdet (2016-03-01)
The earthquake that occurred on May 24, 2013, in the basin of the Sea of Okhotsk with a magnitude of 8.3 was the strongest in this region. We have modeled a possible tsunami caused by such an earthquake. The simulations confirm that the wave heights were sufficiently small because the earthquake epicenter depth was 640 km. We analyze the oscillations of the DART buoys in the vicinity of the earthquake source and show that they were not associated with the tsunami waves. Analysis of the available pressure ga...
The depth effect of earthquakes on tsunami heights in the Sea of Okhotsk
Zaytsev, Andrey; Kostenko, Irina; Kurkin, Andrey; Pelinovsky, Efim; Yalçıner, Ahmet Cevdet (The Scientific and Technological Research Council of Turkey, 2016-01-01)
The earthquake of magnitude M-w = 8.3 that occurred on 24 May 2013 in the Sea of Okhotsk was the most powerful earthquake in the region. Fortunately, the generated tsunami was small because of the deep focal depth (609 km) and was only detected by the nearest Deep-ocean Assessment and Reporting of Tsunamis (DART) buoy records. However, the event highlighted the fact that any earthquakes with similar magnitudes at shallower focal depths would have caused considerable tsunamis. In order to evaluate the effect...
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...
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: