Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.0 on date 21-09-2023 and time 22:27:35 (UTC) in region 4 km E Marradi (FI)

A magnitude ML 1.0 earthquake occured in region: 4 km E Marradi (FI), on

  • 21-09-2023 22:27:35 (UTC)
  • 22-09-2023 00:27:35 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 44.0670, 11.6560 at 7 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
Tredozio FC 7 1212 4351
Palazzuolo sul Senio FI 10 1154 5505
Portico e San Benedetto FC 11 756 6261
Premilcuore FC 14 799 7060
Modigliana FC 15 4560 11620
Rocca San Casciano FC 15 1910 13530
San Godenzo FI 16 1167 14697
Casola Valsenio RA 18 2617 17314
Brisighella RA 20 7639 24953
Dovadola FC 20 1653 26606

Municipalities with at least 50000 inhabitants

An earthquake occurred to
31 Km SW of Faenza (58541 inhabitants)
32 Km S of Imola (69797 inhabitants)
35 Km W of Forlì (117913 inhabitants)
46 Km NE of Firenze (382808 inhabitants)
48 Km W of Cesena (96758 inhabitants)
49 Km E of Prato (191150 inhabitants)
51 Km NE of Scandicci (50609 inhabitants)
54 Km SE of Bologna (386663 inhabitants)
58 Km SW of Ravenna (159116 inhabitants)
61 Km E of Pistoia (90315 inhabitants)
69 Km N of Arezzo (99543 inhabitants)
73 Km W of Rimini (147750 inhabitants)
86 Km S of Ferrara (133155 inhabitants)
87 Km SE of Modena (184973 inhabitants)
87 Km NE of Siena (53903 inhabitants)
96 Km E of Lucca (89046 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 1.0 2023-09-21
22:27:35		 44.0667 11.6558 7 2023-09-21
22:35:01		 Sala Sismica INGV-Roma 121327531
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2023-09-21 22:27:35 ± 0.09
Latitude 44.0667 ± 0.0036
Longitude 11.6558 ± 0.0050
Depth (km) 7 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 121327531

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 409
Semi-minor axis of confidence ellipse (meter) 122
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 125
Circular confidence region, given by single value of horizontal uncertainty (meter) 410.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 90
Number of associated phases, regardless of their use for origin computation 19
Number of defining phases 18
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) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.49553
Number of stations at which the event was observed 13
Number of stations from which data was used for origin computation 12
Magnitude information

ML:1.0

Field Value
Value 1.0
Uncertainty 0.2
Num. used stations 16
Type of magnitude ML
Reference to an origin 121327531
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2023-09-21 22:35:01
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.APEC.HHZ. 2023-09-21T22:28:01.39 3.0 undecidable manual S -0.37 0
IV.CRE.HHZ. 2023-09-21T22:27:45.94 0.6 negative manual P 154 55.0005 50 -0.39 42
IV.VISG.HHZ. 2023-09-21T22:27:44.03 0.3 undecidable manual S 308 22.2555 107 0.07 72
IV.RINC.EHZ. 2023-09-21T22:27:43.53 0.3 undecidable manual S 191 20.3685 108 0.2 70
IV.MOCL.EHZ. 2023-09-21T22:27:43.62 0.3 undecidable manual P 260 38.5281 100 -0.1 69
IV.VMGN.HHZ. 2023-09-21T22:27:42.00 0.3 undecidable manual S 218 15.873 113 0.13 72
IV.RUFI.EHZ. 2023-09-21T22:27:41.48 0.3 undecidable manual P 205 27.9498 104 -0.16 70
IV.BOSL.HHN. 2023-09-21T22:27:41.42 0.1 undecidable manual P 236 27.0507 104 -0.05 95
IT.MOG.HNE. 2023-09-21T22:27:41.81 0.3 undecidable manual S 38 14.4744 115 0.37 68
IV.SFI.EHZ. 2023-09-21T22:27:40.70 0.1 undecidable manual P 140 23.5542 106 -0.09 95
IV.RINC.EHZ. 2023-09-21T22:27:40.40 0.3 undecidable manual P 191 20.3685 108 0.22 70
IV.SEI.HHZ. 2023-09-21T22:27:40.67 0.3 undecidable manual P 267 23.754 106 -0.16 70
IV.VISG.HHZ. 2023-09-21T22:27:40.37 0.3 undecidable manual P 308 22.2555 107 -0.18 70
IV.VMGN.HHZ. 2023-09-21T22:27:39.62 0.1 undecidable manual P 218 15.873 113 0.28 93
IT.MOG.HNE. 2023-09-21T22:27:39.30 0.1 undecidable manual P 38 14.4744 115 0.2 94
IV.LMD.HHN. 2023-09-21T22:27:38.33 0.3 undecidable manual S 74 4.2957 148 -0.34 70
IT.MRR.HGN. 2023-09-21T22:27:38.56 0.3 undecidable manual S 266 4.1958 148 -0.09 74
IT.MRR.HGN. 2023-09-21T22:27:37.49 0.1 undecidable manual P 266 4.1958 148 0.01 100
IV.LMD.HHN. 2023-09-21T22:27:37.34 0.3 undecidable manual P 74 4.2957 148 -0.15 73
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.VMGN.HHN. ML:0.6 0.000046921655000000005 0.2944 AML other m 2023-09-21T22:27:44.04
IV.VMGN.HHE. ML:0.8 0.00006989999999999999 0.12 AML other m 2023-09-21T22:27:42.87
IV.VISG.HHE. ML:0.8 0.0000427 0.16 AML other m 2023-09-21T22:27:44.45
IV.SEI.HHE. ML:1.1 0.00008781480499999999 0.2048 AML other m 2023-09-21T22:27:44.68
IV.SFI.EHE. ML:1.1 0.00008790000000000001 0.22 AML other m 2023-09-21T22:27:44.62
IV.SFI.EHN. ML:0.9 0.000057496825 0.1152 AML other m 2023-09-21T22:27:44.98
IV.VISG.HHN. ML:0.8 0.000043597815 0.1152 AML other m 2023-09-21T22:27:45.11
IV.SEI.HHN. ML:1.3 0.00013641290000000002 0.2176 AML other m 2023-09-21T22:27:45.22
IV.RINC.EHE. ML:1.3 0.00013966555 0.1152 AML other m 2023-09-21T22:27:43.74
IV.RINC.EHN. ML:1.1 0.00008988050000000001 0.256 AML other m 2023-09-21T22:27:45.60
IV.RUFI.EHE. ML:0.4 0.00001474127 0.2176 AML other m 2023-09-21T22:27:45.91
IV.RUFI.EHN. ML:0.7 0.00003112984 0.256 AML other m 2023-09-21T22:27:46.05
IV.MOCL.EHE. ML:1.0 0.00003991798 0.3328 AML other m 2023-09-21T22:27:49.20
IV.MOCL.EHN. ML:1.2 0.00006261614 0.2432 AML other m 2023-09-21T22:27:49.50
IV.CRE.HHE. ML:1.1 0.00003158435 0.1792 AML other m 2023-09-21T22:27:54.28
IV.CRE.HHN. ML:1.2 0.00004086554 0.1792 AML other m 2023-09-21T22:27:54.44
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