Coseismic deformation and triggered landslides of the 2016 Mw 6.2 Amatrice earthquake in Italy

• Published in: Geophysical research letters Vol. 44; no. 3; pp. 1266 - 1274
• Main Authors: Huang, Mong‐Han, Fielding, Eric J., Liang, Cunren, Milillo, Pietro, Bekaert, David, Dreger, Douglas, Salzer, Jacqueline
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 16.02.2017
• Subjects: 2016 Amatrice earthquake; Deformation; Earthquake damage; Earthquakes; Fault lines; geodetic inversion; Geological faults; Grounds; Interferometric synthetic aperture radar; Interferometry; Landslides; Landslides & mudslides; Plate tectonics; Radar; SAR interferometry; Seismic activity; Seismology; Shaking; Slip; States; Strikes; Synthetic aperture radar; triggered deep‐seated landslide; Apennines; Italy, Apennines Mountains; Italy; MED, Italy
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2016GL071687

The Central Apennines in Italy have had multiple moderate‐size but damaging shallow earthquakes. In this study, we optimize the fault geometry and invert for fault slip based on coseismic GPS and interferometric synthetic aperture radar (InSAR) for the 2016 Mw 6.2 Amatrice earthquake in Italy. Our results show that nearly all the fault slip occurred between 3 and 6 km depth but extends 20 km along strike. There was less than 4 cm static surface displacement at the town Amatrice where the most devastating damage occurred. Landslides triggered by earthquake ground shaking are not uncommon, but triggered landslides with submeter movement are challenging to be observed in the field. We find evidence of coseismically triggered deep‐seated landslides northwest and northeast of the epicenter where coseismic peak ground acceleration was estimated >0.5 g. By combining ascending and descending InSAR data, we are able to estimate the landslide thickness as at least 100 and 80 m near Monte Vettore and west of Castelluccio, respectively. The landslide near Monte Vettore terminates on the preexisting fault Monte Vettore Fault (MVEF) scarp. Our results imply that the long‐term fault slip rate of MVEF estimated based on paleoseismic studies could potentially have errors due to triggered landslides from nearby earthquake events. Key Points InSAR can provide coseismic displacement or other hazard response typically within a few days Nearly all of the slip occurred between 3 and 5 km in depth but extends about 20 km along strike The triggered landslide on the Monte Vettore fault may contribute additional fault offset and influence the long‐term fault slip rate