{"id":1550,"date":"2021-10-30T20:01:15","date_gmt":"2021-10-30T18:01:15","guid":{"rendered":"https:\/\/www.gein.noa.gr\/?page_id=1550"},"modified":"2022-02-15T18:00:10","modified_gmt":"2022-02-15T16:00:10","slug":"tectonic-geodesy","status":"publish","type":"page","link":"https:\/\/www.gein.noa.gr\/en\/research\/research-topics\/tectonic-geodesy\/","title":{"rendered":"Tectonic Geodesy"},"content":{"rendered":"
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Tectonic Geodesy focuses on the systematic recording of seismic and aseismic deformation of the Earth’s crust, the study of the seismic cycle and the modeling of seismic rupture and its parameters through the use of geodetic data. In addition, low- and high-rate data from continuously operating GNSS stations are used jointly with seismic data for the most complete and realistic quantification of seismic potential and consequently seismic hazard and risk.<\/span><\/i><\/span><\/h3>\n\n\t\t<\/div>\n\t<\/div>\n<\/div><\/div><\/div>
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Why study this topic? The challenges<\/b><\/h2>\n

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Space geodesy technologies, such as GNSS, are valuable tools for monitoring the deformation of the Earth’s crust and its surface, especially along areas of active tectonics. The high accuracy of the measurements (millimeter scale) and the capabilities of continuous data flow, have revolutionized the understanding of the physical processes that precede, take place during or follow strong earthquakes. For example, GNSS data analysis can reveal which sections of the plate-interface zone are accommodating high strains, decipher the rupture process of strong earthquakes and assess transient postseismic deformation that frequently occurs after large-magnitude earthquakes. During the last two decades, usage of high-rate GNSS data has become very common, given that, contrary to seismometers and strong motion sensors, GNSS stations can directly provide displacement waveforms without saturation or drift. <\/span><\/p>\n

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An important discovery due to GNSS data over the last 20 years or so, is the detection\u00a0of silent earthquakes (or slow-slip events). These earthquakes, like typical earthquakes, release energy in response to the movement of tectonic plates but over a period of time ranging from a few days to months. In several cases it has been observed that silent earthquakes precede large earthquakes, often triggering them. Another important finding using GNSS data is that the locus of a future earthquake, its recurrence and size, largely depends on the mechanical properties (e.g. friction) of the materials that characterize either a large active fault or a plate-interface zone at different depths. Given that space geodesy technologies such as GNSS, are a valuable tool in geosciences and because Greece is located on an active subduction zone, the Institute of Geodynamics has its own permanent GNSS network. It consists of 28 continuously operating GNSS stations with a sampling interval ranging from 0.2 sec to 1 sec. These stations transmit data in real time to the facilities of the Institute of Geodynamics and are freely available to the science community.<\/span><\/p>\n\n\t\t<\/div>\n\t<\/div>\n\n\t

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Our key research activities<\/b><\/span><\/h2>\n

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