EGU23-6973
https://doi.org/10.5194/egusphere-egu23-6973
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

3D geological modeling of the blind thrust system activated during the November 2022 Pesaro offshore seismic sequence (Adriatic sea, Italy).

Francesco Emanuele Maesano1, Mauro Buttinelli1, Roberta Maffucci1, Giovanni Toscani2,3, Roberto Basili1, Lorenzo Bonini4,1, Pierfrancesco Burrato1, Jakub Fedorik5, Umberto Fracassi1, Yuri Panara5, Gabriele Tarabusi1, Mara Monica Tiberti1, Gianluca Valensise1, Roberto Vallone1, and Paola Vannoli1
Francesco Emanuele Maesano et al.
  • 1Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
  • 2Dipartimento di Scienze della Terra e dell’Ambiente, Università di Pavia, Pavia, Italy
  • 3Centro InteRUniversitario per l’Analisi SismoTettonica Tridimensionale con applicazioni territoriali, Chieti, Italy
  • 4Dipartimento di Matematica e Geoscienze, Università di Trieste, Italy
  • 5King Abdullah University of Science and Technology, Thuwal, Saudi Arabia

The undersea portion of the Northern Apennines is characterized by blind thrust faults running parallel to the Adriatic Sea coastline in northeastern peninsular Italy. These thrusts are buried below a thick cover of syntectonic Quaternary deposits. Their elusive geological signature at shallow depths and the low seismicity associated with them gave rise to diverging interpretations and views concerning the current activity of these thrusts and their earthquake potential.

On 9 November 2022, a seismic sequence started with an Mw 5.5 earthquake in the Pesaro Offshore. Hypocentral depth, focal mechanism, and aftershocks location all suggest that the earthquake was generated by one of the outermost thrusts of the Northern Apennines front that was already mapped as a potential seismogenic source in the DISS database (https://diss.ingv.it/diss330/sources.php?ITCS106).

We present a 3D reconstruction of the thrust system that caused the Pesaro Offshore seismic sequence obtained through the reinterpretation of publicly available seismic reflection profiles and well logs. The 3D geometry and size of the thrust activated during the seismic sequence suggest that it can also host larger earthquakes. We also present the application of a well-established workflow for calculating the slip rates of this buried thrust already tested in nearby structures. The outcomes of this study represent a step forward for earthquake and tsunami hazard models, the study of the seismic source, the enhancement of earthquake location by mix and match of seismological and geological independent data, and the expected kinematics of future potential earthquake ruptures.

These results are particularly relevant in offshore areas, where neither surface co-seismic ruptures nor GPS/InSAR deformation data are available in the aftermath of a significant earthquake. In these cases, multichannel seismic reflection profiles represent the only tool to appraise the subsurface structural setting. 

How to cite: Maesano, F. E., Buttinelli, M., Maffucci, R., Toscani, G., Basili, R., Bonini, L., Burrato, P., Fedorik, J., Fracassi, U., Panara, Y., Tarabusi, G., Tiberti, M. M., Valensise, G., Vallone, R., and Vannoli, P.: 3D geological modeling of the blind thrust system activated during the November 2022 Pesaro offshore seismic sequence (Adriatic sea, Italy)., EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6973, https://doi.org/10.5194/egusphere-egu23-6973, 2023.