Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.0 on date 25-09-2023 and time 21:35:23 (UTC) in region 6 km NW Chiusdino (SI)

A magnitude ML 1.0 earthquake occured in region: 6 km NW Chiusdino (SI), on

  • 25-09-2023 21:35:23 (UTC)
  • 25-09-2023 23:35:23 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 43.2000, 11.0470 at 9 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
Chiusdino SI 6 1903 1903
Radicondoli SI 7 914 2817
Montieri GR 8 1204 4021
Castelnuovo di Val di Cecina PI 11 2231 6252
Monticiano SI 13 1571 7823
Casole d'Elsa SI 16 3897 11720
Monterotondo Marittimo GR 17 1371 13091
Sovicille SI 17 10116 23207
Pomarance PI 18 5897 29104

Municipalities with at least 50000 inhabitants

An earthquake occurred to
27 Km SW of Siena (53903 inhabitants)
49 Km N of Grosseto (82087 inhabitants)
63 Km S of Scandicci (50609 inhabitants)
66 Km S of Firenze (382808 inhabitants)
71 Km SE of Livorno (159219 inhabitants)
74 Km W of Arezzo (99543 inhabitants)
76 Km S of Prato (191150 inhabitants)
78 Km SE of Pisa (89158 inhabitants)
82 Km S of Pistoia (90315 inhabitants)
84 Km SE of Lucca (89046 inhabitants)
98 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 1.0 2023-09-25
21:35:23		 43.2005 11.0472 9 2023-09-25
21:48:58		 Sala Sismica INGV-Roma 121455711
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2023-09-25 21:35:23 ± 0.19
Latitude 43.2005 ± 0.0117
Longitude 11.0472 ± 0.0185
Depth (km) 9 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 121455711

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 1747
Semi-minor axis of confidence ellipse (meter) 287
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 129
Circular confidence region, given by single value of horizontal uncertainty (meter) 1750.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 162
Number of associated phases, regardless of their use for origin computation 19
Number of defining phases 10
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.44
Epicentral distance of station closest to the epicenter (degree) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.43078
Number of stations at which the event was observed 14
Number of stations from which data was used for origin computation 5
Magnitude information

ML:1.0

Field Value
Value 1.0
Uncertainty 0.1
Num. used stations 4
Type of magnitude ML
Reference to an origin 121455711
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2023-09-25 21:48:58
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.PAOL.HHZ. 2023-09-25T21:36:58.70 3.0 undecidable manual Sn 3.53 0
OX.ACOM.HHZ. 2023-09-25T21:36:49.76 3.0 undecidable manual Sg 12.03 0
IV.SPS2.HHZ. 2023-09-25T21:36:46.33 3.0 negative manual Pn 5.75 0
IV.MTGR.HHZ. 2023-09-25T21:36:41.52 3.0 undecidable manual Pn 0.46 0
IV.CDRU.HHZ. 2023-09-25T21:36:38.21 3.0 undecidable manual Pg 17.25 0
IV.MCRV.HHZ. 2023-09-25T21:36:21.93 3.0 undecidable manual Pn 4.9 0
GU.TRAV.HHZ. 2023-09-25T21:35:49.53 3.0 positive manual Pn -5.68 0
IV.BRSN.HNZ. 2023-09-25T21:35:41.19 3.0 undecidable manual Sn 0 0
IV.CASP.HHZ. 2023-09-25T21:35:38.69 0.1 undecidable manual S 198 47.8188 50 -0.37 91
IV.CSNT.HHZ. 2023-09-25T21:35:35.39 0.3 undecidable manual S 33 36.0417 50 -0.53 67
IV.CASP.HHZ. 2023-09-25T21:35:33.02 0.1 undecidable manual P 198 47.8188 50 0.57 86
IV.RIBO.EHZ.01 2023-09-25T21:35:33.39 0.1 undecidable manual S 180 27.8499 108 -0.22 97
IV.CSNT.HHZ. 2023-09-25T21:35:30.79 0.1 undecidable manual P 33 36.0417 50 0.15 97
IV.TRIF.CHZ. 2023-09-25T21:35:29.18 0.1 undecidable manual S 231 15.0738 121 -0.37 96
IV.RIBO.EHZ.01 2023-09-25T21:35:29.68 0.1 undecidable manual P 180 27.8499 108 0.37 94
IV.TRIF.CHZ. 2023-09-25T21:35:27.13 0.1 undecidable manual P 231 15.0738 121 0.17 100
IV.FROS.CHZ. 2023-09-25T21:35:27.51 0.1 undecidable manual S 83 8.88 136 -0.34 98
IV.FROS.CHZ. 2023-09-25T21:35:26.41 0.1 undecidable manual P 83 8.88 136 0.43 96
IV.MPPT.EHZ. 2023-09-25T21:35:18.28 3.0 undecidable manual P -0.06 0
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.FROS.CHE. ML:0.9 0.00011295 1.74 AML other m 2023-09-25T21:35:27.99
IV.FROS.CHN. ML:0.9 0.00010515 0.3 AML other m 2023-09-25T21:35:28.29
IV.TRIF.CHE. ML:1.1 0.000136 1.78 AML other m 2023-09-25T21:35:29.89
IV.TRIF.CHN. ML:0.9 0.0000731 1.04 AML other m 2023-09-25T21:35:31.75
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