This evening, at 21:58 Italian time (September 10, 2017), an earthquake of magnitude ML 3.9 (Mw 3.7) was located in the province of L'Aquila, in the Piana del Fucino. The municipalities closest to the epicenter are: Scurcola Marsicana, Magliano de' Marsi and Tagliacozzo (AQ).
The epicenter of tonight's earthquake of magnitude ML 3.9.
The earthquake was felt in the southern part of the province of L'Aquila and in the nearby province of Rome, as evidenced by the more than 200 questionnaires completed so far on http://www.haisentitoilterremoto.it/ and from the seismic effect map in MCS scale (Mercalli-Cancani-Sieberg) which shows the distribution of earthquake effects on the territory.
The seismic effect map in MCS scale (Mercalli-Cancani-Sieberg) showing the distribution of the effects of the earthquake on the territory. The instrumental epicenter of the earthquake is indicated with the purple star, the colored circles refer to the intensities associated with each municipality. The caption above indicates the number of questionnaires processed to obtain the map itself. http://mappe.haisentitoilterremoto.it/17025201/mcs.jpg
Below is the map with the distribution of instrumental intensities. The scale used is the Modified Mercalli Intensity (MMI – Modified Mercalli Intensity) and is based on the recorded values of effective ground shaking in terms of acceleration and ground speed.
This map shows the distribution of instrumental intensities. The scale used is the Modified Mercalli Intensity (MMI – Modified Mercalli Intensity) and is based on the recorded values of effective ground shaking in terms of acceleration and ground velocity. In general, the Mercalli intensity scale is based on the effects that the shaking induces and which is reported by an observer.
Looking at the seismicity map since 1985, it can be seen that the area where the earthquake occurred had little seismic activity, despite being the area affected by the strong earthquake of 1915. The area to the north is, however, characterized by numerous epicenters of the 2009 L'Aquila sequence.
Earthquakes localized by the National Seismic Network in Italy from 1985 to 2016 (source: http://cnt.rm.ingv.it/). The white star is the epicenter of the magnitude 3.9 earthquake.
The Parametric Catalog of Italian Earthquakes (CPTI15) shows that the area of Fucino and Marsica was characterized by the violent earthquake of 13 January 1915, an earthquake which caused very serious damage to Avezzano, throughout the Piana del Fucino and in numerous locations in the Valle Roveto and the middle Liri Valley. The macroseismic intensity, estimated on the basis of the damage distribution, was of the XI degree of the MCS scale, the estimated magnitude (Mw) 7.1.
This evening's earthquake took place in the same area as the earthquake of 24 February 1904 which caused damage to Rosciolo de' Marsi, Scurcola Marsicana, Magliano de' Marsi and in the adjacent towns and villages. The macroseismic intensity, estimated on the basis of the damage distribution, was of the IX degree of the MCS scale, the estimated magnitude Mw 5.7.
Historical seismicity of central Italy (source: CPTI15), superimposed on the seismic hazard (source: http://zonesismiche.mi.ingv.it/). The white star is the epicenter of the magnitude 3.9 earthquake.
Looking at the area of today's event with respect to the Hazard Map of the national territory, it can be seen that it falls within a high hazard area, where the expected acceleration is between 0.225 and 0.250 g, referring to rigid soils with a probability of excess by 10% in 50 years.
Link to the INGVterremoti Blog:
https://ingvterremoti.wordpress.com/2017/09/10/evento-sismico-in-provincia-dellaquila-ml-3-9-mw-3-7-10-settembre-ore-21-58/