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A massive earthquake with a magnitude of 8.8 has hit Chile on February 27, 2010. Precise measurements made by the Doris system have tracked these displacements.

A massive earthquake with a magnitude of 8.8 has hit Chile on February 27, 2010. It took place not so far from the most powerful earthquake ever measured (the Great Chilean Earthquake in 1960 had a magnitude of 9.5). It occured along a 700 km-rupture zone between the Nazca and the South American tectonic plates. A large patch of the seafloor has been abruptly uplifting  and the South American Plate has been moved westward. Few minutes after the first shock, consecutive tsunami waves hit coastal towns and later extended to the coastal areas on the Pacific Ocean. The earthquake and the tsunami caused severe casualties and damage.

Precise measurements made with the Doris system have tracked these movements on land. Doris is a precise orbit determination and positioning technique onboard altimetry and Spot satellites. It includes about 60 ground beacons in an international network of autonomous stations used as reference points on the ground to cover the satellites trajectory continuously. Short delay localization (3 days) of each Doris station are made in the framework of the Ssalto ground segment (See <link internal-link>Ssalto: a new ground segment for a new generation of altimetry satellites in Newsletter #7).

Precise Doris measurements from before and after the earthquake, show that the Santiago antenna, moved about 10-15 cm southward, up to 25 cm westward and about 15 cm downward.

<link fileadmin images news mod_actus doris_seisme_chili_feb2010_balise_santiago.gif download>
Time series of Santiago (Chile) Doris antenna coordinates. Credits IDS.

Further information:

• <link internal-link>Doris, the space surveyor
• Applications: <link internal-link>Geophysics
• IDS, <link http: www.ids-doris.org html doris ids-station-series.php3 _blank external-link-new-window>station coordinate time series