Earthquake with magnitude of ML 1.2 on date 28-09-2020 and time 17:55:20 (Italy) in region 9 km SW Montalcino (SI)

A magnitude ML 1.2 earthquake occured in region: 9 km SW Montalcino (SI), on

  • 28-09-2020 15:55:20 (UTC)
  • 28-09-2020 17:55:20 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 43.01, 11.4 at 5 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
Montalcino SI 9 5093 5093
Civitella Paganico GR 10 3154 8247
Cinigiano GR 14 2618 10865
Buonconvento SI 15 3173 14038
Seggiano GR 16 961 14999
San Quirico d'Orcia SI 17 2662 17661
Castel del Piano GR 17 4690 22351
Castiglione d'Orcia SI 17 2346 24697
Murlo SI 17 2389 27086
Campagnatico GR 18 2412 29498
Roccastrada GR 19 9199 38697
Arcidosso GR 19 4285 42982

Municipalities with at least 50000 inhabitants

An earthquake occurred to
35 Km S of Siena (53903 inhabitants)
37 Km NE of Grosseto (82087 inhabitants)
64 Km SW of Arezzo (99543 inhabitants)
81 Km W of Perugia (166134 inhabitants)
85 Km S of Scandicci (50609 inhabitants)
85 Km S of Firenze (382808 inhabitants)
88 Km NW of Viterbo (67173 inhabitants)
100 Km S of Prato (191150 inhabitants)
Recent and historical Seismicity
Seismic hazard
Shakemap
Felt maps
The earthquake effects in MCS scale as obtained from the compiled questionnaire

The earthquake effects in MCS scale as obtained from the compiled questionnaire

This map shows the distribution of the effects of the earthquake on the territory in terms of the MCS (Mercalli-Cancani-Sieberg) intensity scale. The intensities are determined using the data provided in the questionnaire (http://www.haisentitoilterremoto.it/) that are analysed using robust statistical techniques since they are not verified individually. Specifically, the assignment of MCS intensities greater or equal the VI degree of the MCS scale require opportune in situ verification by professional experts. The purple start shows the epicenter. This map is prepared every so often that the population fill in new questionnaires. The number of questionnaires used to determine the map and the date and time of the last adjournment are shown in the upper right part of the panel.
Locations history
Type Magnitude Date and Time (UTC) Latitude Longitude Depth (km) Published time (UTC) Author Location ID
Reviewed
Rev100
ML 1.2 2020-09-28
15:55:20
43.01 11.4 5 2020-09-28
16:00:39
Sala Sismica INGV-Roma 83336611
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2020-09-28 15:55:20 ± 0.13
Latitude 43.01 ± 0.01
Longitude 11.40 ± 0.01
Depth (km) 5 ± 2 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 83336611

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 985
Semi-minor axis of confidence ellipse (meter) 210
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) 980
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 175
Number of associated phases, regardless of their use for origin computation 13
Number of defining phases 12
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.27
Epicentral distance of station closest to the epicenter (degree) 0
Epicentral distance of station farthest from the epicenter (degree) 0.45236
Number of stations at which the event was observed 8
Number of stations from which data was used for origin computation 7
Magnitude information

ML:1.2

Field Value
Value 1.2
Uncertainty 0.2
Num. used stations 4
Type of magnitude ML
Reference to an origin 83336611
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2020-09-28 16:00:39
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
IV.CRTC.HHZ. 2020-09-28T15:56:04.58 3.0 undecidable manual S 1.54 0
IV.RIBO.EHZ.01 2020-09-28T15:55:30.15 0.3 undecidable manual S 256 0.2689 99 -0.45 69
IV.CASP.HHZ. 2020-09-28T15:55:30.09 0.1 undecidable manual P 241 0.4524 50 -0.02 96
IV.FROS.CHZ. 2020-09-28T15:55:30.48 0.3 undecidable manual S 318 0.2671 99 -0.04 75
TV.SF04.EHZ. 2020-09-28T15:55:29.71 0.3 undecidable manual S 133 0.2581 99 -0.48 68
TV.SF01.EHZ. 2020-09-28T15:55:28.95 0.3 undecidable manual S 150 0.232 100 -0.26 72
IV.ARCI.HHZ. 2020-09-28T15:55:27.18 0.3 undecidable manual S 162 0.1691 104 0.35 71
TV.SF04.EHZ. 2020-09-28T15:55:26.01 0.1 negative manual P 133 0.2581 99 0.07 99
IV.FROS.CHZ. 2020-09-28T15:55:26.15 0.1 negative manual P 318 0.2671 99 0.02 100
IV.RIBO.EHZ.01 2020-09-28T15:55:26.43 0.1 undecidable manual P 256 0.2689 99 0.26 95
IV.MCIV.CHZ. 2020-09-28T15:55:26.92 0.1 negative manual P 139 0.3076 98 -0.11 98
TV.SF01.EHZ. 2020-09-28T15:55:25.54 0.1 undecidable manual P 150 0.232 100 0.17 98
IV.ARCI.HHZ. 2020-09-28T15:55:24.30 0.3 undecidable manual P 162 0.1691 104 0.3 72
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.ARCI.HHE. ML:1.1 0.0001077 0.18 AML other m 2020-09-28T15:55:28.27
IV.ARCI.HHN. ML:0.9 7.205E-5 1.06 AML other m 2020-09-28T15:55:28.39
IV.FROS.CHN. ML:1.4 0.0001142 0.52 AML other m 2020-09-28T15:55:30.35
IV.FROS.CHE. ML:1.3 0.00010165 0.4 AML other m 2020-09-28T15:55:34.46
TDMT - Time Domain Moment Tensor
Focal Mechanism in the area
Download
Type Description Link
QuakeML - small Event, Origin, FocalMechanism Download
QuakeML - full Event, Origin, FocalMechanism, Amplitude, Arrival, Pick, Station Magnitude Download