Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.4 on date 31-10-2020 and time 04:24:12 (UTC) in region 3 km NW Castiglione d'Orcia (SI)

A magnitude ML 1.4 earthquake occured in region: 3 km NW Castiglione d'Orcia (SI), on

  • 31-10-2020 04:24:12 (UTC)
  • 31-10-2020 05:24:12 (UTC +01:00) Italian time

and geographic coordinates (lat, lon) 43.0310, 11.5980 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
Castiglione d'Orcia SI 3 2346 2346
San Quirico d'Orcia SI 3 2662 5008
Pienza SI 9 2107 7115
Montalcino SI 9 5093 12208
Seggiano GR 12 961 13169
San Giovanni d'Asso SI 14 853 14022
Buonconvento SI 15 3173 17195
Castel del Piano GR 16 4690 21885
Montepulciano SI 17 14097 35982
Abbadia San Salvatore SI 18 6444 42426
Arcidosso GR 18 4285 46711
Trequanda SI 19 1254 47965
Chianciano Terme SI 19 7105 55070

Municipalities with at least 50000 inhabitants

An earthquake occurred to
39 Km SE of Siena (53903 inhabitants)
50 Km NE of Grosseto (82087 inhabitants)
54 Km SW of Arezzo (99543 inhabitants)
65 Km W of Perugia (166134 inhabitants)
80 Km NW of Viterbo (67173 inhabitants)
87 Km SE of Firenze (382808 inhabitants)
88 Km SE of Scandicci (50609 inhabitants)
90 Km W of Foligno (57155 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 1.4 2020-10-31
04:24:12		 43.0313 11.5978 9 2020-10-31
04:32:46		 Sala Sismica INGV-Roma 84304601
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2020-10-31 04:24:12 ± 0.24
Latitude 43.0313 ± 0.0144
Longitude 11.5978 ± 0.0209
Depth (km) 9 ± 3 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 84304601

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 1884
Semi-minor axis of confidence ellipse (meter) 1169
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 220
Circular confidence region, given by single value of horizontal uncertainty (meter) 1880.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 126
Number of associated phases, regardless of their use for origin computation 14
Number of defining phases 12
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.38
Epicentral distance of station closest to the epicenter (degree) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.49553
Number of stations at which the event was observed 8
Number of stations from which data was used for origin computation 6
Magnitude information

ML:1.4

Field Value
Value 1.4
Uncertainty 0.4
Num. used stations 8
Type of magnitude ML
Reference to an origin 84304601
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2020-10-31 04:32:46
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.CASP.HHZ. 2020-10-31T04:24:33.41 3.0 undecidable manual S -0.01 0
IV.CSNT.HHE. 2020-10-31T04:24:30.17 0.3 undecidable manual S 333 55.0005 50 0.2 76
IV.CAFI.HNN. 2020-10-31T04:24:26.81 0.1 undecidable manual S 42 44.5221 50 -0.37 100
IV.SACS.HHZ. 2020-10-31T04:24:23.46 0.6 undecidable manual S 129 32.4453 50 -0.49 50
IV.CSNT.HHE. 2020-10-31T04:24:22.08 0.1 undecidable manual P 333 55.0005 50 -0.46 96
IV.CAFI.HNN. 2020-10-31T04:24:21.30 0.1 undecidable manual P 42 44.5221 50 0.38 100
IV.MGAB.HHZ. 2020-10-31T04:24:21.48 3.0 positive manual P -0.24 0
TV.SF01.EHZ. 2020-10-31T04:24:21.45 0.6 undecidable manual S 187 24.4533 110 0.02 56
IV.ARCI.HHZ. 2020-10-31T04:24:20.42 0.6 undecidable manual S 207 22.2555 112 -0.28 53
TV.SF04.EHZ. 2020-10-31T04:24:20.09 0.6 undecidable manual S 167 22.2555 112 -0.62 48
IV.SACS.HHZ. 2020-10-31T04:24:19.73 0.1 undecidable manual P 129 32.4453 50 0.67 93
TV.SF01.EHZ. 2020-10-31T04:24:17.61 1.0 negative manual P 187 24.4533 110 0 28
IV.ARCI.HHZ. 2020-10-31T04:24:17.41 0.3 negative manual P 207 22.2555 112 0.23 80
TV.SF04.EHZ. 2020-10-31T04:24:17.50 0.6 undecidable manual P 167 22.2555 112 0.31 53
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
TV.SF04.EHN. ML:1.6 0.000286 1.8 AML other m 2020-10-31T04:24:21.06
TV.SF04.EHE. ML:1.8 0.0003985 0.2 AML other m 2020-10-31T04:24:21.13
IV.ARCI.HHN. ML:1.1 0.00008824999999999999 0.96 AML other m 2020-10-31T04:24:21.55
TV.SF01.EHE. ML:1.6 0.00023799999999999998 0.24 AML other m 2020-10-31T04:24:21.85
TV.SF01.EHN. ML:1.9 0.0004735 0.24 AML other m 2020-10-31T04:24:21.71
IV.ARCI.HHE. ML:1.0 0.0000708 1.3 AML other m 2020-10-31T04:24:23.66
IV.MGAB.HHE. ML:1.0 0.000034500000000000005 0.14 AML other m 2020-10-31T04:24:29.84
IV.MGAB.HHN. ML:1.0 0.000032550000000000005 0.6 AML other m 2020-10-31T04:24:30.36
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