Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 0.8 on date 18-09-2023 and time 06:51:36 (UTC) in region 2 km SW Marradi (FI)

A magnitude ML 0.8 earthquake occured in region: 2 km SW Marradi (FI), on

  • 18-09-2023 06:51:36 (UTC)
  • 18-09-2023 08:51:36 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 44.0630, 11.6020 at 11 km depth.

The earthquake was located by: Sala Sismica INGV-Roma.

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.

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Municipalities within 20 km from the epicenter

Distances are determinated based on the geographic coordintes of the (Istat).
Municipality Region Dist Inh Cum Inh
Marradi FI 2 3139 3139
Palazzuolo sul Senio FI 7 1154 4293
Tredozio FC 12 1212 5505
Portico e San Benedetto FC 15 756 6261
San Godenzo FI 15 1167 7428
Premilcuore FC 17 799 8227
Vicchio FI 18 8044 16271
Casola Valsenio RA 18 2617 18888
Castel del Rio BO 19 1246 20134
Modigliana FC 19 4560 24694
Firenzuola FI 19 4726 29420
Rocca San Casciano FC 19 1910 31330
Dicomano FI 20 5515 36845

Municipalities with at least 50000 inhabitants

An earthquake occurred to
34 Km SW of Faenza (58541 inhabitants)
34 Km S of Imola (69797 inhabitants)
39 Km W of Forlì (117913 inhabitants)
43 Km NE of Firenze (382808 inhabitants)
45 Km E of Prato (191150 inhabitants)
48 Km NE of Scandicci (50609 inhabitants)
52 Km W of Cesena (96758 inhabitants)
52 Km SE of Bologna (386663 inhabitants)
57 Km E of Pistoia (90315 inhabitants)
62 Km SW of Ravenna (159116 inhabitants)
70 Km NW of Arezzo (99543 inhabitants)
77 Km W of Rimini (147750 inhabitants)
84 Km SE of Modena (184973 inhabitants)
86 Km N of Siena (53903 inhabitants)
86 Km S of Ferrara (133155 inhabitants)
91 Km E of Lucca (89046 inhabitants)
98 Km SE of Carpi (70699 inhabitants)
Recent and historical seismicity
Seismic hazard
Shakemap
Felt maps
Locations history
Type Magnitude Date and Time (UTC) Latitude Longitude Depth (km) Published time (UTC) Author Location ID
Reviewed
Rev100 		ML 0.8 2023-09-18
06:51:36		 44.0632 11.602 11 2023-09-18
07:00:25		 Sala Sismica INGV-Roma 121167251
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2023-09-18 06:51:36 ± 0.1
Latitude 44.0632 ± 0.0045
Longitude 11.6020 ± 0.0075
Depth (km) 11 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 121167251

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 663
Semi-minor axis of confidence ellipse (meter) 347
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 243
Circular confidence region, given by single value of horizontal uncertainty (meter) 660.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 176
Number of associated phases, regardless of their use for origin computation 14
Number of defining phases 14
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.19
Epicentral distance of station closest to the epicenter (degree) 0.11961
Epicentral distance of station farthest from the epicenter (degree) 0.23652
Number of stations at which the event was observed 7
Number of stations from which data was used for origin computation 7
Magnitude information

ML:0.8

Field Value
Value 0.8
Uncertainty 0.1
Num. used stations 2
Type of magnitude ML
Reference to an origin 121167251
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2023-09-18 07:00:25
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.RUFI.EHZ. 2023-09-18T06:51:46.04 0.6 undecidable manual S 197 26.0517 50 0.05 49
IV.BOSL.HHE. 2023-09-18T06:51:45.04 0.6 undecidable manual S 231 23.3544 50 -0.23 48
IV.SFI.EHZ. 2023-09-18T06:51:45.90 0.6 undecidable manual S 132 26.2515 50 -0.15 48
IV.RINC.EHZ. 2023-09-18T06:51:44.33 0.6 undecidable manual S 179 19.5693 118 0.14 49
IV.SEI.HHZ. 2023-09-18T06:51:44.22 0.3 undecidable manual S 267 19.4694 119 0.08 74
IV.VISG.HHZ. 2023-09-18T06:51:44.00 0.3 undecidable manual S 316 19.3695 119 -0.11 74
IV.RUFI.EHZ. 2023-09-18T06:51:42.05 0.3 undecidable manual P 197 26.0517 50 0.09 73
IV.SFI.EHZ. 2023-09-18T06:51:41.87 0.3 undecidable manual P 132 26.2515 50 -0.13 72
IV.VMGN.HHN. 2023-09-18T06:51:41.84 0.3 undecidable manual S 205 13.2756 129 -0.51 68
IV.RINC.EHZ. 2023-09-18T06:51:41.05 0.1 undecidable manual P 179 19.5693 118 0.12 98
IV.BOSL.HHE. 2023-09-18T06:51:41.80 0.6 undecidable manual P 231 23.3544 50 0.25 47
IV.VISG.HHZ. 2023-09-18T06:51:40.86 0.1 undecidable manual P 316 19.3695 119 -0.02 100
IV.VMGN.HHN. 2023-09-18T06:51:40.13 0.1 undecidable manual P 205 13.2756 129 0.27 96
IV.SEI.HHZ. 2023-09-18T06:51:40.92 0.3 undecidable manual P 267 19.4694 119 0.02 75
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.SFI.EHN. ML:0.8 0.0000359 0.76 AML other m 2023-09-18T06:51:46.05
IV.SFI.EHE. ML:0.7 0.00003145 0.34 AML other m 2023-09-18T06:51:46.86
TDMT - Time Domain Moment Tensor
Fault Plane solutions in the area
Download
Type Description Link
QuakeML - small Event, Origin, FocalMechanism Download
QuakeML - full Event, Origin, FocalMechanism, Amplitude, Arrival, Pick, Station Magnitude Download