Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 0.9 on date 18-09-2023 and time 22:34:25 (UTC) in region 4 km N Marradi (FI)

A magnitude ML 0.9 earthquake occured in region: 4 km N Marradi (FI), on

  • 18-09-2023 22:34:25 (UTC)
  • 19-09-2023 00:34:25 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 44.1140, 11.6200 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 4 3139 3139
Palazzuolo sul Senio FI 6 1154 4293
Tredozio FC 11 1212 5505
Casola Valsenio RA 12 2617 8122
Castel del Rio BO 14 1246 9368
Modigliana FC 15 4560 13928
Portico e San Benedetto FC 16 756 14684
Fontanelice BO 17 1943 16627
Brisighella RA 17 7639 24266
Borgo Tossignano BO 18 3288 27554
Rocca San Casciano FC 19 1910 29464
Firenzuola FI 19 4726 34190
Premilcuore FC 20 799 34989
Riolo Terme RA 20 5720 40709

Municipalities with at least 50000 inhabitants

An earthquake occurred to
28 Km S of Imola (69797 inhabitants)
29 Km SW of Faenza (58541 inhabitants)
36 Km W of Forlì (117913 inhabitants)
48 Km SE of Bologna (386663 inhabitants)
48 Km NE of Firenze (382808 inhabitants)
49 Km NE of Prato (191150 inhabitants)
50 Km W of Cesena (96758 inhabitants)
53 Km NE of Scandicci (50609 inhabitants)
57 Km SW of Ravenna (159116 inhabitants)
60 Km E of Pistoia (90315 inhabitants)
75 Km N of Arezzo (99543 inhabitants)
76 Km W of Rimini (147750 inhabitants)
80 Km S of Ferrara (133155 inhabitants)
81 Km SE of Modena (184973 inhabitants)
91 Km N of Siena (53903 inhabitants)
94 Km E of Lucca (89046 inhabitants)
95 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 0.9 2023-09-18
22:34:25		 44.1137 11.6198 11 2023-09-18
23:02:34		 Sala Sismica INGV-Roma 121211411
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2023-09-18 22:34:25 ± 0.21
Latitude 44.1137 ± 0.0135
Longitude 11.6198 ± 0.0163
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 121211411

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 1640
Semi-minor axis of confidence ellipse (meter) 998
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 146
Circular confidence region, given by single value of horizontal uncertainty (meter) 1640.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 169
Number of associated phases, regardless of their use for origin computation 23
Number of defining phases 18
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.4
Epicentral distance of station closest to the epicenter (degree) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.28688
Number of stations at which the event was observed 14
Number of stations from which data was used for origin computation 9
Magnitude information

ML:0.9

Field Value
Value 0.9
Uncertainty 0.3
Num. used stations 12
Type of magnitude ML
Reference to an origin 121211411
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2023-09-18 23:02:34
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.TERO.HHZ. 2023-09-18T22:35:21.63 3.0 undecidable manual Sg 7.85 0
IV.SENI.EHE. 2023-09-18T22:34:44.86 3.0 undecidable manual Pg 3.97 0
IV.COR1.EHZ. 2023-09-18T22:34:38.15 3.0 negative manual Pg -0.25 0
IV.SFI.EHZ. 2023-09-18T22:34:36.03 1.0 undecidable manual S 142 29.4483 50 0.54 22
IV.MURB.HHE. 2023-09-18T22:34:36.37 3.0 undecidable manual P -0.33 0
IV.BOSL.HHZ. 2023-09-18T22:34:35.23 0.3 undecidable manual S 224 28.1496 50 0.06 74
IV.RUFI.EHZ. 2023-09-18T22:34:35.49 0.6 undecidable manual S 196 31.8459 50 -0.65 42
IV.SEI.HHZ. 2023-09-18T22:34:33.47 0.6 undecidable manual S 253 21.867 50 0 50
IV.RINC.EHZ. 2023-09-18T22:34:33.76 0.3 undecidable manual S 182 25.2525 50 -0.62 65
IV.VMGN.HHZ. 2023-09-18T22:34:32.07 0.6 undecidable manual S 202 18.9699 119 -0.59 44
IV.BRSN.EHE. 2023-09-18T22:34:32.67 3.0 negative manual P 0.08 0
IV.BOSL.HHZ. 2023-09-18T22:34:31.06 0.1 undecidable manual P 224 28.1496 50 0.15 97
IV.RUFI.EHZ. 2023-09-18T22:34:31.42 0.1 undecidable manual P 196 31.8459 50 -0.05 98
IV.SFI.EHZ. 2023-09-18T22:34:31.57 0.3 undecidable manual P 142 29.4483 50 0.47 68
IV.RINC.EHZ. 2023-09-18T22:34:30.53 1.0 negative manual P 182 25.2525 50 0.07 25
IT.MOG.HNE. 2023-09-18T22:34:30.30 0.3 undecidable manual S 62 13.2756 129 -0.72 63
IV.SEI.HHZ. 2023-09-18T22:34:30.33 0.6 undecidable manual P 253 21.867 50 0.39 46
IV.LMD.HHN. 2023-09-18T22:34:30.30 0.6 undecidable manual S 120 8.0808 143 0.55 45
IV.VMGN.HHZ. 2023-09-18T22:34:29.52 0.1 undecidable manual P 202 18.9699 119 0.06 100
IT.MRR.HGE. 2023-09-18T22:34:28.83 0.6 undecidable manual S 193 5.6943 152 -0.47 47
IV.LMD.HHN. 2023-09-18T22:34:28.60 0.1 undecidable manual P 120 8.0808 143 0.82 82
IT.MRR.HGE. 2023-09-18T22:34:27.81 0.1 undecidable manual P 193 5.6943 152 0.28 98
IT.MOG.HNE. 2023-09-18T22:34:27.85 0.3 undecidable manual P 62 13.2756 129 -0.67 65
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.LMD.HHN. ML:1.0 0.00014295405 0.1152 AML other m 2023-09-18T22:34:30.39
IV.LMD.HHE. ML:0.8 0.00009458499500000001 0.1408 AML other m 2023-09-18T22:34:30.42
IV.SEI.HHE. ML:1.0 0.0000618054 0.2688 AML other m 2023-09-18T22:34:33.58
IV.SEI.HHN. ML:1.2 0.0000955 0.38 AML other m 2023-09-18T22:34:37.49
IV.RINC.EHE. ML:0.9 0.000048312029999999996 0.192 AML other m 2023-09-18T22:34:34.27
IV.RINC.EHN. ML:0.7 0.000029692935 0.128 AML other m 2023-09-18T22:34:34.38
IV.RUFI.EHE. ML:0.4 0.000008408945000000002 0.6016 AML other m 2023-09-18T22:34:43.02
IV.RUFI.EHN. ML:0.5 0.000016164989999999998 0.2432 AML other m 2023-09-18T22:34:35.60
IV.SFI.EHE. ML:0.6 0.0000177435685 0.2816 AML other m 2023-09-18T22:34:35.82
IV.SFI.EHN. ML:0.6 0.000018232073500000002 0.2048 AML other m 2023-09-18T22:34:36.23
IV.SFI.HNE. ML:1.4 0.000124413965 3.0464 AML other m 2023-09-18T22:34:38.82
IV.SFI.HNN. ML:1.4 0.00011936924 1.9968 AML other m 2023-09-18T22:34:40.85
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