Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 0.9 on date 18-09-2021 and time 23:43:12 (Italy) in region 5 km N Montieri (GR)

A magnitude ML 0.9 earthquake occured in region: 5 km N Montieri (GR), on

  • 18-09-2021 21:43:12 (UTC)
  • 18-09-2021 23:43:12 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 43.1770, 11.0270 at 10 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
Montieri GR 5 1204 1204
Chiusdino SI 6 1903 3107
Radicondoli SI 10 914 4021
Castelnuovo di Val di Cecina PI 10 2231 6252
Monticiano SI 13 1571 7823
Monterotondo Marittimo GR 14 1371 9194
Massa Marittima GR 18 8375 17569
Casole d'Elsa SI 18 3897 21466
Pomarance PI 19 5897 27363

Municipalities with at least 50000 inhabitants

An earthquake occurred to
29 Km SW of Siena (53903 inhabitants)
47 Km N of Grosseto (82087 inhabitants)
66 Km S of Scandicci (50609 inhabitants)
69 Km S of Firenze (382808 inhabitants)
72 Km SE of Livorno (159219 inhabitants)
76 Km W of Arezzo (99543 inhabitants)
78 Km SE of Pisa (89158 inhabitants)
79 Km S of Prato (191150 inhabitants)
85 Km S of Pistoia (90315 inhabitants)
86 Km SE of Lucca (89046 inhabitants)
99 Km SE of Viareggio (62467 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 2021-09-18
21:43:12		 43.1773 11.0273 10 2021-09-18
21:55:56		 Sala Sismica INGV-Roma 95603161
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-09-18 21:43:12 ± 0.18
Latitude 43.1773 ± 0.0126
Longitude 11.0273 ± 0.0160
Depth (km) 10 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 95603161

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 1609
Semi-minor axis of confidence ellipse (meter) 755
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 142
Circular confidence region, given by single value of horizontal uncertainty (meter) 1610.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 157
Number of associated phases, regardless of their use for origin computation 9
Number of defining phases 8
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) 0.35163
Number of stations at which the event was observed 5
Number of stations from which data was used for origin computation 4
Magnitude information

ML:0.9

Field Value
Value 0.9
Uncertainty 0.3
Num. used stations 10
Type of magnitude ML
Reference to an origin 95603161
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-09-18 21:55:56
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.CSNT.HHZ. 2021-09-18T21:43:25.06 0.3 undecidable manual S 33 39.0276 50 -0.5 67
IV.RIBO.EHZ.01 2021-09-18T21:43:21.53 0.3 undecidable manual S 176 25.3524 111 -0.32 71
IV.CSNT.HHZ. 2021-09-18T21:43:20.24 0.1 undecidable manual P 33 39.0276 50 0.24 95
IV.RIBO.EHZ.01 2021-09-18T21:43:18.13 0.1 undecidable manual P 176 25.3524 111 0.27 96
IV.FROS.CHZ. 2021-09-18T21:43:17.33 0.1 undecidable manual S 71 10.9779 132 -0.21 100
IV.TRIF.CHZ. 2021-09-18T21:43:17.56 0.1 undecidable manual S 236 12.2766 129 -0.3 98
IV.TRIF.CHZ. 2021-09-18T21:43:15.79 0.1 undecidable manual P 236 12.2766 129 0.23 99
IV.FROS.CHZ. 2021-09-18T21:43:15.71 0.1 undecidable manual P 71 10.9779 132 0.34 97
IV.CASP.HHZ. 2021-09-18T21:42:37.97 3.0 undecidable manual P 0.07 0
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.CASP.HHE. ML:0.5 0.000010799555 0.64 AML other m 2021-09-18T21:42:43.89
IV.CASP.HHN. ML:0.5 0.0000102707415 0.32 AML other m 2021-09-18T21:42:43.78
IV.CASP.HNN. ML:1.6 0.00012889779500000002 0.8576 AML other m 2021-09-18T21:42:48.11
IV.FROS.CHE. ML:1.1 0.0001440723 0.192 AML other m 2021-09-18T21:42:34.13
IV.FROS.CHN. ML:1.2 0.00017529044999999997 0.0768 AML other m 2021-09-18T21:42:34.18
IV.TRIF.CHE. ML:1.0 0.00010947401500000001 0.704 AML other m 2021-09-18T21:42:34.73
IV.TRIF.CHN. ML:1.0 0.00011307075 0.0768 AML other m 2021-09-18T21:42:35.05
IV.RIBO.EHE.01 ML:0.9 0.000049936565 1.4208 AML other m 2021-09-18T21:42:38.22
IV.CSNT.HHN. ML:0.4 0.0000105203735 0.2304 AML other m 2021-09-18T21:42:41.90
IV.CSNT.HHE. ML:0.4 0.0000088816572 0.1408 AML other m 2021-09-18T21:42:42.05
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