Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.2 on date 27-10-2020 and time 19:54:37 (Italy) in region 4 km NW Castiglione d'Orcia (SI)

A magnitude ML 1.2 earthquake occured in region: 4 km NW Castiglione d'Orcia (SI), on

  • 27-10-2020 18:54:37 (UTC)
  • 27-10-2020 19:54:37 (UTC +01:00) Italian time

and geographic coordinates (lat, lon) 43.0230, 11.5770 at 8 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.

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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 4 2346 2346
San Quirico d'Orcia SI 5 2662 5008
Montalcino SI 8 5093 10101
Pienza SI 10 2107 12208
Seggiano GR 11 961 13169
Castel del Piano GR 15 4690 17859
San Giovanni d'Asso SI 15 853 18712
Buonconvento SI 15 3173 21885
Arcidosso GR 17 4285 26170
Abbadia San Salvatore SI 18 6444 32614
Montepulciano SI 18 14097 46711
Trequanda SI 20 1254 47965

Municipalities with at least 50000 inhabitants

An earthquake occurred to
38 Km SE of Siena (53903 inhabitants)
48 Km NE of Grosseto (82087 inhabitants)
55 Km SW of Arezzo (99543 inhabitants)
67 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)
92 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
Bulletin
Rev1000 		ML 1.2 2020-10-27
18:54:37		 43.0227 11.577 8 2021-02-26
14:56:13		 Bollettino Sismico Italiano INGV 86027301
Reviewed
Rev100 		ML 1.3 2020-10-27
18:54:38		 43.0065 11.5798 13 2020-10-27
19:12:49		 Sala Sismica INGV-Roma 84187921
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2020-10-27 18:54:37 ± 0.15
Latitude 43.0227 ± 0.0099
Longitude 11.5770 ± 0.0098
Depth (km) 8 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-INGV
Event type earthquake
Origin ID 86027301

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 1117
Semi-minor axis of confidence ellipse (meter) 694
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 195
Circular confidence region, given by single value of horizontal uncertainty (meter) 1120.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 68
Number of associated phases, regardless of their use for origin computation 30
Number of defining phases 21
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.32
Epicentral distance of station closest to the epicenter (degree) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.49643
Number of stations at which the event was observed 19
Number of stations from which data was used for origin computation 11
Magnitudes information

ML:1.2

Field Value
Value 1.2
Uncertainty 0.3
Num. used stations 9
Type of magnitude ML
Reference to an origin 86027301
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2021-01-05 11:02:32

ML:1.3

Field Value
Value 1.3
Uncertainty 0.2
Num. used stations 7
Type of magnitude ML
Reference to an origin 84187921
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2020-10-27 19:12:49
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
MN.TRI.HHZ. 2020-10-27T18:56:23.43 3.0 undecidable manual Sg 13.54 0
IV.SARZ.HHZ. 2020-10-27T18:55:53.65 3.0 undecidable manual Sg 5.46 0
IV.PETRA.HHZ. 2020-10-27T18:55:51.75 3.0 negative manual Pn -0.81 0
CH.BERNI.HHZ. 2020-10-27T18:55:36.22 3.0 negative manual Pg 4.99 0
IV.BSSO.HHZ. 2020-10-27T18:55:22.93 3.0 negative manual Pg 5.02 0
GU.GSCL.HHZ. 2020-10-27T18:55:19.91 3.0 undecidable manual Sn -4.16 0
IV.SARZ.HHZ. 2020-10-27T18:55:13.61 3.0 positive manual Pn -2.34 0
IV.ARRO.EHZ. 2020-10-27T18:55:10.37 3.0 undecidable manual Sn -2.16 0
IV.BRSN.EHZ. 2020-10-27T18:55:05.87 3.0 negative manual Pg 2.82 0
IV.CSNT.HHZ. 2020-10-27T18:54:55.41 0.3 undecidable manual S 335 55.1004 50 -0.22 68
IV.RIBO.EHZ.01 2020-10-27T18:54:52.56 0.6 undecidable manual S 259 43.8228 50 -0.06 47
IV.MGAB.HHZ. 2020-10-27T18:54:52.37 0.6 undecidable manual S 106 45.1215 50 -0.6 47
IV.FROS.CHZ. 2020-10-27T18:54:51.44 0.3 undecidable manual S 301 39.9267 50 -0.14 74
IV.SACS.HHZ. 2020-10-27T18:54:50.35 0.6 undecidable manual S 125 33.1446 104 0.61 36
IV.MGAB.HHZ. 2020-10-27T18:54:47.14 0.3 undecidable manual P 106 45.1215 50 0.56 62
IV.CSNT.HHZ. 2020-10-27T18:54:47.87 0.1 undecidable manual P 335 55.1004 50 -0.26 90
IV.CAFI.HNZ. 2020-10-27T18:54:46.74 0.3 undecidable manual P 43 46.3203 50 -0.03 72
TV.SF01.EHZ. 2020-10-27T18:54:46.02 0.3 undecidable manual S 183 23.3544 110 -0.47 71
IV.ARCI.HHZ. 2020-10-27T18:54:46.05 0.3 undecidable manual S 204 20.6682 112 0.44 71
IV.FROS.CHZ. 2020-10-27T18:54:45.99 0.3 undecidable manual P 301 39.9267 50 0.21 72
IV.SACS.HHZ. 2020-10-27T18:54:45.00 0.3 undecidable manual P 125 33.1446 104 0.28 69
TV.SF13.HHE. 2020-10-27T18:54:45.78 0.6 undecidable manual S 171 22.9548 110 -0.55 46
IV.RIBO.EHZ.01 2020-10-27T18:54:45.94 0.6 undecidable manual P 259 43.8228 50 -0.45 46
TV.SF04.EHZ. 2020-10-27T18:54:45.43 0.1 undecidable manual S 162 21.867 111 -0.55 91
TV.SF11.HHE. 2020-10-27T18:54:44.58 0.3 undecidable manual S 154 18.9699 114 -0.49 68
IV.ARCI.HHZ. 2020-10-27T18:54:42.56 0.1 undecidable manual P 204 20.6682 112 0.23 100
TV.SF04.EHZ. 2020-10-27T18:54:42.82 0.1 undecidable manual P 162 21.867 111 0.27 99
TV.SF13.HHE. 2020-10-27T18:54:42.93 0.1 undecidable manual P 171 22.9548 110 0.17 100
TV.SF11.HHE. 2020-10-27T18:54:42.34 0.3 undecidable manual P 154 18.9699 114 0.32 74
TV.SF01.EHZ. 2020-10-27T18:54:42.94 0.3 undecidable manual P 183 23.3544 110 0.09 76
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
TV.SF04.EHN. ML:1.4 0.00015820285 0.1152 AML other m 2020-10-27T18:54:45.46
IV.ARCI.HHE. ML:0.8 0.000045115909999999993 0.128 AML other m 2020-10-27T18:54:46.52
TV.SF04.EHE. ML:1.5 0.00021620978499999998 0.2432 AML other m 2020-10-27T18:54:46.85
IV.ARCI.HHN. ML:0.8 0.000045236175000000004 1.6416 AML other m 2020-10-27T18:54:46.03
TV.SF01.EHE. ML:1.2 0.00010895622499999999 1.7184 AML other m 2020-10-27T18:54:46.14
TV.SF01.EHN. ML:1.5 0.00022145055 1.7568 AML other m 2020-10-27T18:54:47.00
IV.RIBO.EHE.01 ML:1.4 0.000079933615 0.2816 AML other m 2020-10-27T18:54:53.85
IV.CSNT.HHN. ML:1.0 0.00002607126 0.3488 AML other m 2020-10-27T18:54:55.81
IV.CSNT.HHE. ML:1.2 0.000042219245 1.4912 AML other m 2020-10-27T18:54:59.96
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