Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of Md 1.1 on date 21-09-2023 and time 21:31:26 (UTC) in region 4 km E Marradi (FI)

A magnitude Md 1.1 earthquake occured in region: 4 km E Marradi (FI), on

  • 21-09-2023 21:31:26 (UTC)
  • 21-09-2023 23:31:26 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 44.0660, 11.6620 at 6 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
Rocca San Casciano FC 15 1910 8970
Modigliana FC 15 4560 13530
San Godenzo FI 16 1167 14697
Casola Valsenio RA 18 2617 17314
Dovadola FC 19 1653 18967
Brisighella RA 19 7639 26606

Municipalities with at least 50000 inhabitants

An earthquake occurred to
30 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)
47 Km W of Cesena (96758 inhabitants)
50 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)
72 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 		Md 1.1 2023-09-21
21:31:26		 44.0665 11.6618 6 2023-09-21
21:55:01		 Sala Sismica INGV-Roma 121325561
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2023-09-21 21:31:26 ± 0.11
Latitude 44.0665 ± 0.0036
Longitude 11.6618 ± 0.0050
Depth (km) 6 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 121325561

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 400
Semi-minor axis of confidence ellipse (meter) 125
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 108
Circular confidence region, given by single value of horizontal uncertainty (meter) 400.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 89
Number of associated phases, regardless of their use for origin computation 43
Number of defining phases 16
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.21
Epicentral distance of station closest to the epicenter (degree) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.49373
Number of stations at which the event was observed 36
Number of stations from which data was used for origin computation 9
Magnitude information

Md:1.1

Field Value
Value 1.1
Uncertainty 0.3
Num. used stations 5
Type of magnitude Md
Reference to an origin 121325561
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2023-09-21 21:55:01
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.VULT.HHZ. 2023-09-21T21:31:51.15 3.0 undecidable manual Pg 22.26 0
IV.MCRV.HHZ. 2023-09-21T21:31:43.61 3.0 undecidable manual Pg 16.1 0
GU.SATI.HHZ. 2023-09-21T21:31:43.53 3.0 undecidable manual Pg 13.46 0
IV.CRE.HHZ. 2023-09-21T21:31:35.82 0.6 undecidable manual P 155 54.8007 50 -0.7 38
IV.SFI.EHZ. 2023-09-21T21:31:34.50 0.3 undecidable manual S 140 23.2545 105 0.11 72
IV.VISG.HHZ. 2023-09-21T21:31:34.34 0.3 undecidable manual S 307 22.6551 105 0.15 71
IV.RINC.EHZ. 2023-09-21T21:31:33.62 0.3 undecidable manual S 192 20.4684 107 0.16 71
IV.VMGN.HHZ. 2023-09-21T21:31:32.39 0.6 undecidable manual S 220 16.1727 111 0.35 46
IT.MOG.HNE. 2023-09-21T21:31:31.77 0.3 undecidable manual S 36 14.2746 114 0.34 69
IV.RINC.EHZ. 2023-09-21T21:31:30.56 0.3 undecidable manual P 192 20.4684 107 0.24 70
IV.VISG.HHZ. 2023-09-21T21:31:30.60 0.3 undecidable manual P 307 22.6551 105 -0.14 71
IV.SFI.EHZ. 2023-09-21T21:31:30.79 0.3 undecidable manual P 140 23.2545 105 -0.07 72
IV.SEI.HHZ. 2023-09-21T21:31:30.89 0.3 undecidable manual P 267 24.2535 104 -0.16 71
IV.VMGN.HHZ. 2023-09-21T21:31:29.47 0.6 undecidable manual P 220 16.1727 111 -0.04 49
IT.MOG.HNE. 2023-09-21T21:31:29.32 0.1 undecidable manual P 36 14.2746 114 0.17 96
IV.LMD.HHZ. 2023-09-21T21:31:28.33 0.1 undecidable manual S 71 3.7962 148 -0.25 96
IT.MRR.HGZ. 2023-09-21T21:31:28.62 0.1 undecidable manual S 267 4.6953 143 -0.12 99
IV.LMD.HHZ. 2023-09-21T21:31:27.42 0.1 undecidable manual P 71 3.7962 148 -0.08 100
IT.MRR.HGZ. 2023-09-21T21:31:27.55 0.1 undecidable manual P 267 4.6953 143 -0.05 100
IV.ARRO.EHZ. 2023-09-21T21:31:14.50 3.0 positive manual Pg 13.14 0
IV.CASP.HHZ. 2023-09-21T21:31:03.21 3.0 positive manual Pn 2.1 0
IV.BARO.EHZ. 2023-09-21T21:31:01.87 3.0 undecidable manual Pn -0.47 0
GU.GRAM.HHZ. 2023-09-21T21:31:01.51 3.0 undecidable manual Pn -5.2 0
IV.MOMA.HHZ. 2023-09-21T21:31:00.32 3.0 undecidable manual Pn 0.57 0
IV.MF5.EHZ. 2023-09-21T21:31:00.14 3.0 negative manual P -2.28 0
MN.VLC.HHZ. 2023-09-21T21:31:00.04 3.0 undecidable manual Pn -3.38 0
IV.RM33.EHZ. 2023-09-21T21:31:00.67 3.0 positive manual P -2.66 0
IV.LNSS.HHZ. 2023-09-21T21:31:00.31 3.0 positive manual P -1.82 0
IV.NRCA.HHZ. 2023-09-21T21:31:00.04 3.0 positive manual Pn -1.33 0
GU.MAIM.HHZ. 2023-09-21T21:31:00.61 3.0 undecidable manual Pn -1.42 0
IV.ATCC.EHZ. 2023-09-21T21:31:00.25 3.0 positive manual Pn 1.49 0
IV.FOSV.EHZ. 2023-09-21T21:31:00.06 3.0 positive manual Pn 1.11 0
GU.EQUI.HHZ. 2023-09-21T21:30:59.03 3.0 undecidable manual Pn -5.62 0
IV.SMA1.EHZ. 2023-09-21T21:30:59.89 3.0 undecidable manual Pn -3.32 0
IV.FRON.EHZ. 2023-09-21T21:30:59.40 3.0 positive manual Pn 0.61 0
IV.MML1.EHZ. 2023-09-21T21:30:59.35 3.0 undecidable manual Pn -0.6 0
IV.FDMO.HHZ. 2023-09-21T21:30:59.58 3.0 undecidable manual Pn -1.01 0
IV.GUMA.HHZ. 2023-09-21T21:30:59.39 3.0 undecidable manual Pn -2.22 0
IV.SNTG.HHZ. 2023-09-21T21:30:59.34 3.0 undecidable manual Pn -0.25 0
IV.CSP1.EHZ. 2023-09-21T21:30:59.44 3.0 undecidable manual Pn -1.51 0
IV.MPAG.EHZ. 2023-09-21T21:30:59.37 3.0 positive manual Pn 0.38 0
IV.CING.HHZ. 2023-09-21T21:30:58.03 3.0 undecidable manual Pn -2.49 0
IV.SACS.HHZ. 2023-09-21T21:30:55.76 3.0 undecidable manual Pn -3.06 0
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