Under the Prosecco vineyards: microearthquakes give new insights to the seismic sources of eastern Southern Alps 

In August 2021, an extremely productive seismic sequence occurred in northeastern Italy. In one month, 407 microearthquakes were identified and localised in the area monitored by the local Collalto Seismic Network. This is about 20 times the average monthly rate of events detected over the last decade. Most of them are located under the village of Refrontolo (in the Veneto region) at a depth of about 9 km; the main event has a magnitude MW = 2.4, and none of these earthquakes were felt by the population.

The earthquakes, identified by automatic procedures, were manually post-processed and relocated using different techniques. The peculiarity of this study is that, through the analysis of this copious group of microearthquakes, much larger than the average, it has been possible to define a small South-East dipping volume that deviates from the brittle surface previously enlightened by microseisms and assigned to the North-North West dipping Montello thrust.

The study also shows that the episode, which is insignificant from an energetic point of view, may be of greatest interest for deciphering the seismic potential of this area and for strengthening automatic microearthquake detection and location procedures.

Photo: Autumn in Prosecco Hills. Credit: Guido Andolfato on Visualhunt