The Vertical Coseismic Deformation Field of the Samos-Izmir Earthquake (Mw6.9)

Author(s):  
Muharrem Hilmi Erkoç ◽  
Seda Özarpacı ◽  
Alpay Özdemir ◽  
Figen Eskiköy ◽  
Efe Turan Ayruk ◽  
...  

<p>The Samos-Izmir Earthquake (Mw=6.9) of October 30, 2020 is among the strongest earthquakes that occurred in recent years throughout the Eastern Aegean. The epicenter of this earthquake was 14 km away from Samos Island and 25 km away from Gümüldür-İzmir region. The local tsunami with the wave heights reaching ~2m was triggered by the mainshock. The most affected areas were Sigacik and Akarca in Tukey (Yalciner et. al.,2020) and Vathy Town (NE Samos Island) in Greece (Triantafyllou et. al.,2020).</p><p>In this study, we present an estimation of co-seismic deformations using an indirect approach based on GNSS, InSAR and Tide Gauge data. GNSS time series were used from 25 continuous GNSS stations data obtained from TUSAGA-Aktif in Turkey and NOANET in Greek, and the campaign GNSS measurement for 10 GNSS sites located at the western Turkey coast has been carried out after the earthquake. Moreover, InSAR deformation analyses have been performed using Sentinel-1 data. In addition, relative sea level changes have been analyzed in KOS, PLOMARI, and MENTES tide gauge stations.</p><p>The vertical components of GPS stations have shown 10 cm uplift in Samos Island and 10 cm subsidence in the coast of Turkey. The results of the geodetic (GNSS, InSAR) analysis are consistent with each other. The rise time estimated here may correspond to the time elapsed shortly before the generation of tsunami waves reached up to 6 meters that propagated rapidly and caused significant damage around the source region. Also, it has been seen that whereas relative sea level in KOS and PLOMARI tide gauge stations are affected by the local tsunami, but relative sea level changes could not be observed in the MENTES station.</p>

2021 ◽  
Author(s):  
Ben S. Hague ◽  
David A. Jones ◽  
Blair Trewin ◽  
Doerte Jakob ◽  
Bradley F. Murphy ◽  
...  

2021 ◽  
Vol 21 (8) ◽  
pp. 2643-2678 ◽  
Author(s):  
Davide Zanchettin ◽  
Sara Bruni ◽  
Fabio Raicich ◽  
Piero Lionello ◽  
Fanny Adloff ◽  
...  

Abstract. The city of Venice and the surrounding lagoonal ecosystem are highly vulnerable to variations in relative sea level. In the past ∼150 years, this was characterized by an average rate of relative sea-level rise of about 2.5 mm/year resulting from the combined contributions of vertical land movement and sea-level rise. This literature review reassesses and synthesizes the progress achieved in quantification, understanding and prediction of the individual contributions to local relative sea level, with a focus on the most recent studies. Subsidence contributed to about half of the historical relative sea-level rise in Venice. The current best estimate of the average rate of sea-level rise during the observational period from 1872 to 2019 based on tide-gauge data after removal of subsidence effects is 1.23 ± 0.13 mm/year. A higher – but more uncertain – rate of sea-level rise is observed for more recent years. Between 1993 and 2019, an average change of about +2.76 ± 1.75 mm/year is estimated from tide-gauge data after removal of subsidence. Unfortunately, satellite altimetry does not provide reliable sea-level data within the Venice Lagoon. Local sea-level changes in Venice closely depend on sea-level variations in the Adriatic Sea, which in turn are linked to sea-level variations in the Mediterranean Sea. Water mass exchange through the Strait of Gibraltar and its drivers currently constitute a source of substantial uncertainty for estimating future deviations of the Mediterranean mean sea-level trend from the global-mean value. Regional atmospheric and oceanic processes will likely contribute significant interannual and interdecadal future variability in Venetian sea level with a magnitude comparable to that observed in the past. On the basis of regional projections of sea-level rise and an understanding of the local and regional processes affecting relative sea-level trends in Venice, the likely range of atmospherically corrected relative sea-level rise in Venice by 2100 ranges between 32 and 62 cm for the RCP2.6 scenario and between 58 and 110 cm for the RCP8.5 scenario, respectively. A plausible but unlikely high-end scenario linked to strong ice-sheet melting yields about 180 cm of relative sea-level rise in Venice by 2100. Projections of human-induced vertical land motions are currently not available, but historical evidence demonstrates that they have the potential to produce a significant contribution to the relative sea-level rise in Venice, exacerbating the hazard posed by climatically induced sea-level changes.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
T. C. Harvey ◽  
B. D. Hamlington ◽  
T. Frederikse ◽  
R. S. Nerem ◽  
C. G. Piecuch ◽  
...  

AbstractRegional sea-level changes are caused by several physical processes that vary both in space and time. As a result of these processes, large regional departures from the long-term rate of global mean sea-level rise can occur. Identifying and understanding these processes at particular locations is the first step toward generating reliable projections and assisting in improved decision making. Here we quantify to what degree contemporary ocean mass change, sterodynamic effects, and vertical land motion influence sea-level rise observed by tide-gauge locations around the contiguous U.S. from 1993 to 2018. We are able to explain tide gauge-observed relative sea-level trends at 47 of 55 sampled locations. Locations where we cannot explain observed trends are potentially indicative of shortcomings in our coastal sea-level observational network or estimates of uncertainty.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
H. Bâki Iz ◽  
C. K. Shum ◽  
C. Zhang ◽  
C. Y. Kuo

AbstractThis study demonstrates that relative sea level trends calculated from long-term tide gauge records can be used to estimate relative vertical crustal velocities in a region with high accuracy. A comparison of the weighted averages of the relative sea level trends estimated at six tide gauge stations in two clusters along the Eastern coast of United States, in Florida and in Maryland, reveals a statistically significant regional vertical crustal motion of Maryland with respect to Florida with a subsidence rate of −1.15±0.15 mm/yr identified predominantly due to the ongoing glacial isostatic adjustment process. The estimate is a consilience value to validate vertical crustal velocities calculated from GPS time series as well as towards constraining predictive GIA models in these regions.


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