Earthquake with magnitude of ML 1.3 on date 18-09-2021 and time 07:21:55 (Italy) in region 10 km S Montieri (GR)

A magnitude ML 1.3 earthquake occured in region: 10 km S Montieri (GR), on

  • 18-09-2021 05:21:55 (UTC)
  • 18-09-2021 07:21:55 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 43.048, 11.048 at 3 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.

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 10 1204 1204
Roccastrada GR 11 9199 10403
Chiusdino SI 13 1903 12306
Massa Marittima GR 13 8375 20681
Monticiano SI 15 1571 22252
Gavorrano GR 18 8580 30832
Monterotondo Marittimo GR 19 1371 32203
Civitella Paganico GR 20 3154 35357

Municipalities with at least 50000 inhabitants

An earthquake occurred to
32 Km N of Grosseto (82087 inhabitants)
38 Km SW of Siena (53903 inhabitants)
80 Km S of Scandicci (50609 inhabitants)
82 Km S of Firenze (382808 inhabitants)
82 Km SE of Livorno (159219 inhabitants)
82 Km SW of Arezzo (99543 inhabitants)
91 Km SE of Pisa (89158 inhabitants)
93 Km S of Prato (191150 inhabitants)
99 Km SE of Lucca (89046 inhabitants)
99 Km S of Pistoia (90315 inhabitants)
Recent and historical seismicity
Seismic hazard
Felt maps
Preliminary map of the earthquake effects from the web questionnaire

Preliminary map of the earthquake effects from the web questionnaire

This map shows the distribution of earthquake resentment in the area, expressed in terms of intensity on the MCS scale (Mercalli-Cancani-Sieberg). Intensities are determined using data from questionnaires collected on the website The intensities shown are determined considering all the reports received from each municipality, and are all the more reliable the greater the number of questionnaires. The collected data are subjected to an automatic statistical filter, but are not checked individually. In particular, intensities greater than or equal to the VI degree of the MCS or EMS scale require on-site verification by specialized personnel. The black star is the epicenter of the earthquake that occurred. This map is updated every time citizens fill out new questionnaires. The number of questionnaires processed to obtain this map, the date and time of the last update are shown at the top right.
Locations history
Type Magnitude Date and Time (UTC) Latitude Longitude Depth (km) Published time (UTC) Author Location ID
ML 1.3 2021-09-18
43.0475 11.0482 3 2021-09-18
Sala Sismica INGV-Roma 95571941
Preferred location and magnitude until now.
Origin information


Field Value
Time (UTC) 2021-09-18 05:21:55 ± 0.13
Latitude 43.0475 ± 0.0063
Longitude 11.0482 ± 0.0086
Depth (km) 3 ± 2 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 95571941


Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 669
Semi-minor axis of confidence ellipse (meter) 240
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 258
Circular confidence region, given by single value of horizontal uncertainty (meter) 670
Confidence level of the uncertainty (%) 68


Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 96
Number of associated phases, regardless of their use for origin computation 9
Number of defining phases 9
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.31
Epicentral distance of station closest to the epicenter (degree) 0.12591
Epicentral distance of station farthest from the epicenter (degree) 0.68259
Number of stations at which the event was observed 5
Number of stations from which data was used for origin computation 5
Magnitude information


Field Value
Value 1.3
Uncertainty 0.2
Num. used stations 14
Type of magnitude ML
Reference to an origin 95571941
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-09-18 05:31:06
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
IV.CELB.HHZ. 2021-09-18T05:22:10.02 0.1 undecidable manual P 244 0.6826 50 -0.1 91
IV.ARCI.HHZ. 2021-09-18T05:22:09.65 0.3 undecidable manual S 122 0.3687 94 -0.54 66
IV.CASP.HHZ. 2021-09-18T05:22:07.13 0.3 undecidable manual S 208 0.2896 95 -0.02 75
IV.ARCI.HHZ. 2021-09-18T05:22:04.53 0.1 undecidable manual P 122 0.3687 94 0.36 92
IV.FROS.CHZ. 2021-09-18T05:22:02.90 0.3 undecidable manual S 26 0.1799 98 -0.07 76
IV.CASP.HHZ. 2021-09-18T05:22:02.91 1.0 undecidable manual P 208 0.2896 95 0.49 23
IV.FROS.CHZ. 2021-09-18T05:22:00.13 0.1 undecidable manual P 26 0.1799 98 0.13 100
IV.TRIF.CHZ. 2021-09-18T05:22:00.54 0.3 undecidable manual S 302 0.1259 101 -0.36 72
IV.TRIF.CHZ. 2021-09-18T05:21:59.01 0.1 negative manual P 302 0.1259 101 0.2 100
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.TRIF.CHE. ML:1.4 0.00031137125 0.0544 AML other m 2021-09-18T05:22:00.96
IV.TRIF.CHN. ML:1.3 0.0002275012 0.0864 AML other m 2021-09-18T05:22:00.64
IV.FROS.CHE. ML:1.4 0.0002181983 0.1824 AML other m 2021-09-18T05:22:02.94
IV.FROS.CHN. ML:1.6 0.00033349655 0.1696 AML other m 2021-09-18T05:22:02.95
IV.CASP.HHE. ML:1.4 0.00010535 0.22 AML other m 2021-09-18T05:22:07.47
IV.CASP.HHN. ML:1.4 0.00013 0.24 AML other m 2021-09-18T05:22:07.42
IV.ARCI.HHN. ML:1.1 4.495E-5 0.12 AML other m 2021-09-18T05:22:09.80
IV.ARCI.HHE. ML:1 3.73132425E-5 0.16 AML other m 2021-09-18T05:22:09.87
IV.CASP.HNE. ML:1.5 0.00013279642 0.7104 AML other m 2021-09-18T05:22:15.37
IV.CASP.HNN. ML:1.6 0.00019036705 0.2528 AML other m 2021-09-18T05:22:07.42
IV.ARCI.HNE. ML:1.1 4.5454621E-5 0.5888 AML other m 2021-09-18T05:22:06.35
IV.ARCI.HNN. ML:1.1 3.8783675E-5 0.1088 AML other m 2021-09-18T05:22:09.81
IV.CELB.HHE. ML:1.2 2.6540005E-5 0.8416 AML other m 2021-09-18T05:22:09.71
IV.CELB.HHN. ML:1.8 9.065387E-5 1.3984 AML other m 2021-09-18T05:22:35.99
TDMT - Time Domain Moment Tensor
Fault Plane solutions in the area
Type Description Link
QuakeML - small Event, Origin, FocalMechanism Download
QuakeML - full Event, Origin, FocalMechanism, Amplitude, Arrival, Pick, Station Magnitude Download