Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.6 on date 18-09-2021 and time 08:36:29 (Italy) in region 6 km S Montieri (GR)

A magnitude ML 1.6 earthquake occured in region: 6 km S Montieri (GR), on

  • 18-09-2021 06:36:29 (UTC)
  • 18-09-2021 08:36:29 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 43.0820, 11.0370 at 10 km depth.

The earthquake was located by: Bollettino Sismico Italiano INGV.

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.

Hai sentito il terremoto? Clicca qui

Did you feel it? Fill in the questionnaire.

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 6 1204 1204
Chiusdino SI 9 1903 3107
Massa Marittima GR 13 8375 11482
Roccastrada GR 13 9199 20681
Monticiano SI 13 1571 22252
Monterotondo Marittimo GR 16 1371 23623
Castelnuovo di Val di Cecina PI 18 2231 25854
Radicondoli SI 20 914 26768

Municipalities with at least 50000 inhabitants

An earthquake occurred to
36 Km SW of Siena (53903 inhabitants)
36 Km N of Grosseto (82087 inhabitants)
76 Km S of Scandicci (50609 inhabitants)
79 Km S of Firenze (382808 inhabitants)
79 Km SE of Livorno (159219 inhabitants)
81 Km SW of Arezzo (99543 inhabitants)
87 Km SE of Pisa (89158 inhabitants)
89 Km S of Prato (191150 inhabitants)
95 Km SE of Lucca (89046 inhabitants)
95 Km S of Pistoia (90315 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
Bulletin
Rev1000 		ML 1.6 2021-09-18
06:36:29		 43.0818 11.0373 10 2022-03-30
13:04:07		 Bollettino Sismico Italiano INGV 95691441
Reviewed
Rev100 		ML 1.6 2021-09-18
06:36:29		 43.0798 11.0253 11 2021-09-18
06:40:49		 Sala Sismica INGV-Roma 95575241
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-09-18 06:36:29 ± 0.13
Latitude 43.0818 ± 0.0072
Longitude 11.0373 ± 0.0148
Depth (km) 10 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-INGV
Event type earthquake
Origin ID 95691441

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 1203
Semi-minor axis of confidence ellipse (meter) 516
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 284
Circular confidence region, given by single value of horizontal uncertainty (meter) 1200.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 92
Number of associated phases, regardless of their use for origin computation 25
Number of defining phases 15
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.39
Epicentral distance of station closest to the epicenter (degree) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.69158
Number of stations at which the event was observed 18
Number of stations from which data was used for origin computation 8
Magnitudes information

ML:1.6

Field Value
Value 1.6
Uncertainty 0.3
Num. used stations 8
Type of magnitude ML
Reference to an origin 95575241
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-09-18 06:40:49

ML:1.6

Field Value
Value 1.6
Uncertainty 0.3
Num. used stations 8
Type of magnitude ML
Reference to an origin 95691441
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2021-09-21 08:55:42
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
MN.PDG.HHZ. 2021-09-18T06:38:05.27 3.0 undecidable manual Pn 2.11 0
IV.RESU.HHZ. 2021-09-18T06:38:03.40 3.0 undecidable manual Pn 3.57 0
GU.BURY.HHZ. 2021-09-18T06:37:54.74 3.0 undecidable manual Sg 6.81 0
SL.LJU.BHZ. 2021-09-18T06:37:35.87 3.0 undecidable manual Pn 3.37 0
IV.IOCA.HHZ. 2021-09-18T06:37:26.57 3.0 positive manual Pg 4.04 0
IV.SENI.EHZ. 2021-09-18T06:37:26.16 3.0 undecidable manual Sn -1.76 0
IV.CADC.EHZ. 2021-09-18T06:37:10.70 3.0 negative manual Pn -1.88 0
IV.PP3.EHZ. 2021-09-18T06:37:08.81 3.0 negative manual Pg 3.21 0
IV.MTRZ.HNZ. 2021-09-18T06:36:55.63 3.0 undecidable manual P -0.83 0
IV.OSSC.HHE. 2021-09-18T06:36:45.68 0.3 undecidable manual S 19 51.8037 50 -0.06 70
IV.CSNT.HHZ. 2021-09-18T06:36:44.56 0.6 undecidable manual S 25 47.9187 50 -0.15 46
IV.CELB.HHZ. 2021-09-18T06:36:43.50 0.3 undecidable manual P 241 76.7676 50 0.89 52
IV.ARCI.HHZ. 2021-09-18T06:36:43.10 0.6 undecidable manual S 126 43.7229 50 -0.49 43
IV.CASP.HHZ. 2021-09-18T06:36:40.49 0.6 undecidable manual S 203 35.1426 50 -0.81 38
IV.OSSC.HHE. 2021-09-18T06:36:39.25 0.3 undecidable manual P 19 51.8037 50 0.49 64
IV.CSNT.HHZ. 2021-09-18T06:36:37.47 0.3 undecidable manual P 25 47.9187 50 -0.7 59
IV.ARCI.HHZ. 2021-09-18T06:36:37.90 0.3 undecidable manual P 126 43.7229 50 0.38 66
IV.CASP.HHZ. 2021-09-18T06:36:36.26 0.3 undecidable manual P 203 35.1426 50 0.06 72
IV.RIBO.EHZ.01 2021-09-18T06:36:35.19 0.6 undecidable manual S 177 14.7741 124 -0.25 48
IV.FROS.CHZ. 2021-09-18T06:36:35.79 0.6 undecidable manual S 34 17.1717 121 -0.35 46
IV.FROS.CHZ. 2021-09-18T06:36:33.58 0.1 negative manual P 34 17.1717 121 0.36 93
IV.TRIF.CHZ. 2021-09-18T06:36:33.89 0.3 undecidable manual S 289 11.4774 131 -0.66 43
IV.RIBO.EHZ.01 2021-09-18T06:36:32.99 0.1 positive manual P 177 14.7741 124 0.17 97
IV.TRIF.CHZ. 2021-09-18T06:36:32.34 0.1 negative manual P 289 11.4774 131 0.04 100
IV.MAGO.CHZ. 2021-09-18T06:36:27.35 3.0 undecidable manual P 0
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.FROS.CHE. ML:1.5 0.00029099999999999997 0.6 AML other m 2021-09-18T06:36:36.34
IV.FROS.CHN. ML:1.7 0.00039049999999999995 0.4 AML other m 2021-09-18T06:36:36.34
IV.CASP.HHE. ML:1.6 0.000147 0.36 AML other m 2021-09-18T06:36:40.82
IV.CASP.HHN. ML:1.6 0.000177 0.28 AML other m 2021-09-18T06:36:40.78
IV.ARCI.HHN. ML:1.3 0.00006115 1.26 AML other m 2021-09-18T06:36:43.29
IV.ARCI.HHE. ML:1.3 0.00006695 1.56 AML other m 2021-09-18T06:36:44.07
IV.CELB.HHE. ML:1.9 0.00011999999999999999 1 AML other m 2021-09-18T06:37:08.50
IV.CELB.HHN. ML:2.1 0.00020250000000000002 0.08 AML other m 2021-09-18T06:37:08.50
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