Earthquake with magnitude of ML 0.8 on date 23-12-2011 and time 08:15:54 (Italy) in region 4 km W Portico e San Benedetto (FC)

A magnitude ML 0.8 earthquake occured in region: 4 km W Portico e San Benedetto (FC), on

  • 23-12-2011 07:15:54 (UTC)
  • 23-12-2011 08:15:54 (UTC +01:00) Italian time

and geographic coordinates (lat, lon) 44.02, 11.74 at 11 km depth.

The earthquake was located by: Bollettino Sismico Italiano INGV.

Search earthquakes: Any within 30 km radius

The values of hypocentral coordinates and magnitude may be revised at a later time as more information becomes available.

Municipalities within 20 km from the epicenter

Distances are determinated based on the geographic coordintes of the (Istat).
Municipality Region Dist Inh Cum Inh
Portico e San Benedetto FC 4 756 756
Premilcuore FC 5 799 1555
Tredozio FC 7 1212 2767
Rocca San Casciano FC 10 1910 4677
Marradi FI 12 3139 7816
San Godenzo FI 13 1167 8983
Galeata FC 14 2516 11499
Santa Sofia FC 16 4136 15635
Civitella di Romagna FC 16 3786 19421
Modigliana FC 17 4560 23981
Dovadola FC 17 1653 25634
Palazzuolo sul Senio FI 19 1154 26788

Municipalities with at least 50000 inhabitants

An earthquake occurred to
32 Km SW of Faenza (58541 inhabitants)
34 Km SW of Forlì (117913 inhabitants)
38 Km S of Imola (69797 inhabitants)
43 Km W of Cesena (96758 inhabitants)
47 Km NE of Firenze (382808 inhabitants)
53 Km NE of Scandicci (50609 inhabitants)
53 Km E of Prato (191150 inhabitants)
58 Km SW of Ravenna (159116 inhabitants)
62 Km SE of Bologna (386663 inhabitants)
62 Km N of Arezzo (99543 inhabitants)
66 Km E of Pistoia (90315 inhabitants)
67 Km W of Rimini (147750 inhabitants)
84 Km NE of Siena (53903 inhabitants)
92 Km S of Ferrara (133155 inhabitants)
95 Km W of Pesaro (94582 inhabitants)
95 Km SE of Modena (184973 inhabitants)
Recent and historical Seismicity
Seismic hazard
Felt maps
The earthquake effects in MCS scale as obtained from the compiled questionnaire

The earthquake effects in MCS scale as obtained from the compiled questionnaire

This map shows the distribution of the effects of the earthquake on the territory in terms of the MCS (Mercalli-Cancani-Sieberg) intensity scale. The intensities are determined using the data provided in the questionnaire ( that are analysed using robust statistical techniques since they are not verified individually. Specifically, the assignment of MCS intensities greater or equal the VI degree of the MCS scale require opportune in situ verification by professional experts. The purple start shows the epicenter. This map is prepared every so often that the population fill in new questionnaires. The number of questionnaires used to determine the map and the date and time of the last adjournment are shown in the upper right part of the panel.
Locations history
Type Magnitude Date and Time (UTC) Latitude Longitude Depth (km) Published time (UTC) Author Location ID
Rev 1000 Md 1.5
ML 0.8
44.02 11.74 11 2014-10-21
Bollettino Sismico Italiano INGV 1325209
Preferred location and magnitude until now.
Origin information


Field Value
Time (UTC) 2011-12-23 07:15:54 ± 0.15
Latitude 44.02 ± 0.02
Longitude 11.74 ± 0.00
Depth (km) 11 ± 0 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-SISPICK
Event type earthquake
Origin ID 1325209


Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 1842
Semi-minor axis of confidence ellipse (meter) 211
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 7
Circular confidence region, given by single value of horizontal uncertainty (meter) 1726.3
Confidence level of the uncertainty (%) 68


Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 226
Number of associated phases, regardless of their use for origin computation 6
Number of defining phases 6
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.18
Epicentral distance of station closest to the epicenter (degree) 0.1367
Epicentral distance of station farthest from the epicenter (degree) 0.27339
Number of stations at which the event was observed 3
Number of stations from which data was used for origin computation 3
Magnitudes information


Field Value
Value 0.8
Uncertainty 0
Num. used stations
Type of magnitude ML
Reference to an origin 1325209
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-06 02:21:32


Field Value
Value 1.5
Uncertainty 0.3
Num. used stations
Type of magnitude Md
Reference to an origin 1325209
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-06 02:21:32
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
IV.SEI.SHE. 2011-12-23T07:16:05.40 0.3 undecidable manual Sg 278 0.2734 -0.108 73
IV.SEI.SHE. 2011-12-23T07:16:01.03 0.3 undecidable manual Pg 278 0.2734 -0.02 74
IV.SFI.EHZ. 2011-12-23T07:16:01.55 0.3 undecidable manual Sg 144 0.1367 0.084 75
IV.VMG.SHZ. 2011-12-23T07:16:01.66 0.3 undecidable manual Sg 249 0.1475 -0.125 74
IV.VMG.SHZ. 2011-12-23T07:15:59.05 0.1 undecidable manual Pg 249 0.1475 0.151 99
IV.SFI.EHZ. 2011-12-23T07:15:58.64 0.1 undecidable manual Pg 144 0.1367 -0.075 100
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.SFI.EHN. ML:0.8 5.5E-5 0.51 AML other m 2011-12-23T07:15:58.64
IV.SFI.EHE. ML:0.8 5.5E-5 0.51 AML other m 2011-12-23T07:15:58.64
IV.SFI.EHZ. Md:1.2 10.8 END duration s
IV.VMG.SHZ. Md:1.8 19 END duration s
IV.SEI.SHE. Md:1.4 11 END duration s
TDMT - Time Domain Moment Tensor
Focal Mechanism in the area
Type Description Link
QuakeML - small Event, Origin, FocalMechanism Download
QuakeML - full Event, Origin, FocalMechanism, Amplitude, Arrival, Pick, Station Magnitude Download