Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.0 on date 23-02-2021 and time 10:29:10 (Italy) in region 2 km S Spoleto (PG)

A magnitude ML 1.0 earthquake occured in region: 2 km S Spoleto (PG), on

  • 23-02-2021 09:29:10 (UTC)
  • 23-02-2021 10:29:10 (UTC +01:00) Italian time

and geographic coordinates (lat, lon) 42.72, 12.74 at 11 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
Spoleto PG 2 38218 38218
Scheggino PG 7 461 38679
Sant'Anatolia di Narco PG 8 564 39243
Vallo di Nera PG 11 364 39607
Campello sul Clitunno PG 12 2442 42049
Ferentillo TR 12 1913 43962
Castel Ritaldi PG 13 3278 47240
Montefranco TR 14 1276 48516
Arrone TR 15 2763 51279
Poggiodomo PG 16 117 51396
Acquasparta TR 16 4778 56174
Polino TR 17 233 56407
Trevi PG 17 8469 64876
Cerreto di Spoleto PG 18 1075 65951
Giano dell'Umbria PG 18 3846 69797
Monteleone di Spoleto PG 19 599 70396
Massa Martana PG 19 3770 74166
Terni TR 19 111501 185667
San Gemini TR 20 5018 190685

Municipalities with at least 50000 inhabitants

An earthquake occurred to
19 Km NE of Terni (111501 inhabitants)
26 Km S of Foligno (57155 inhabitants)
52 Km SE of Perugia (166134 inhabitants)
62 Km NE of Viterbo (67173 inhabitants)
68 Km NW of L'Aquila (69753 inhabitants)
79 Km W of Teramo (54892 inhabitants)
80 Km N of Guidonia Montecelio (88673 inhabitants)
84 Km N of Tivoli (56533 inhabitants)
94 Km N of Roma (2864731 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 1.0 2021-02-23
09:29:10		 42.72 12.74 11 2021-02-23
09:38:35		 Sala Sismica INGV-Roma 87406281
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-02-23 09:29:10 ± 0.12
Latitude 42.72 ± 0.01
Longitude 12.74 ± 0.01
Depth (km) 11 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 87406281

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 1043
Semi-minor axis of confidence ellipse (meter) 489
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 221
Circular confidence region, given by single value of horizontal uncertainty (meter) 1040
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 185
Number of associated phases, regardless of their use for origin computation 27
Number of defining phases 12
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.2
Epicentral distance of station closest to the epicenter (degree) 0
Epicentral distance of station farthest from the epicenter (degree) 0.4038
Number of stations at which the event was observed 21
Number of stations from which data was used for origin computation 6
Magnitude information

ML:1

Field Value
Value 1
Uncertainty 0.6
Num. used stations 10
Type of magnitude ML
Reference to an origin 87406281
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-02-23 09:38:35
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
IV.QLNO.HHZ. 2021-02-23T09:30:54.82 3.0 undecidable manual Sg 14.66 0
IV.CELI.HNZ. 2021-02-23T09:30:52.42 3.0 undecidable manual Sn 3.22 0
IV.ILOS.HHZ. 2021-02-23T09:30:51.78 3.0 undecidable manual Sn 1.23 0
IV.SPS2.HHZ. 2021-02-23T09:30:48.26 3.0 undecidable manual Sn -0.56 0
AC.VLO.HHZ. 2021-02-23T09:30:36.29 3.0 positive manual Pg 14.92 0
IV.NDIM.HHZ. 2021-02-23T09:30:35.99 3.0 undecidable manual Sg 14.7 0
IV.ESAL.HHZ. 2021-02-23T09:30:31.97 3.0 positive manual Pg 19.98 0
IV.CMDO.HHZ. 2021-02-23T09:30:31.54 3.0 positive manual Pg 20.1 0
MN.CLTB.HHZ. 2021-02-23T09:30:20.16 3.0 positive manual Pg 11.31 0
IV.IFIL.HHZ. 2021-02-23T09:30:14.74 3.0 undecidable manual Pg 15.33 0
IV.SGO.HHZ. 2021-02-23T09:30:12.81 3.0 undecidable manual Sn -0.77 0
IV.MTMR.EHZ. 2021-02-23T09:30:04.24 3.0 undecidable manual Sn 0.41 0
IV.CSNT.HHZ. 2021-02-23T09:29:48.31 3.0 undecidable manual Sn 0.61 0
IV.FDMO.HHZ. 2021-02-23T09:29:24.44 0.6 undecidable manual S 39 0.4038 50 -0.01 50
IV.MF5.EHZ. 2021-02-23T09:29:24.95 3.0 undecidable manual Pg 4.73 0
IV.RIBO.EHZ.01 2021-02-23T09:29:21.21 3.0 undecidable manual Pn -2.62 0
IV.CESI.HHZ. 2021-02-23T09:29:21.28 0.6 undecidable manual S 23 0.3076 50 -0.31 47
IV.NRCA.HHZ. 2021-02-23T09:29:21.32 0.3 undecidable manual S 68 0.295 50 0.1 75
IV.LNSS.HHE. 2021-02-23T09:29:19.36 0.6 undecidable manual S 118 0.2491 50 -0.5 46
IV.FDMO.HHZ. 2021-02-23T09:29:18.49 1.0 positive manual P 39 0.4038 50 0.14 24
IV.NRCA.HHZ. 2021-02-23T09:29:16.59 0.1 undecidable manual P 68 0.295 50 0.11 99
IV.CESI.HHZ. 2021-02-23T09:29:16.81 0.3 undecidable manual P 23 0.3076 50 0.11 74
IV.MOMA.HHZ. 2021-02-23T09:29:16.75 0.3 undecidable manual S 303 0.1511 123 -0.2 75
IV.GAVE.EHZ. 2021-02-23T09:29:15.56 0.6 undecidable manual S 105 0.1151 131 -0.27 50
IV.LNSS.HHE. 2021-02-23T09:29:15.81 0.1 undecidable manual P 118 0.2491 50 0.12 100
IV.MOMA.HHZ. 2021-02-23T09:29:14.19 0.6 positive manual P 303 0.1511 123 0.18 50
IV.GAVE.EHZ. 2021-02-23T09:29:13.71 0.6 positive manual P 105 0.1151 131 0.35 49
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.RM33.EHE. ML:1.1 3.51E-5 0.44 AML other m 2021-02-23T09:29:15.84
IV.RM33.EHN. ML:1.1 3.93E-5 0.34 AML other m 2021-02-23T09:29:15.70
IV.MOMA.HHE. ML:1 7.56E-5 0.2 AML other m 2021-02-23T09:29:17.31
IV.MOMA.HHN. ML:0.8 5.67E-5 0.16 AML other m 2021-02-23T09:29:17.60
IV.NRCA.HHN. ML:0.8 2.905E-5 0.1 AML other m 2021-02-23T09:29:21.56
IV.NRCA.HHE. ML:1 3.895E-5 0.12 AML other m 2021-02-23T09:29:22.34
IV.ILOS.HNE. ML:4.7 0.001265 0.56 AML other m 2021-02-23T09:31:02.61
IV.ILOS.HNN. ML:4.6 0.001064 0.58 AML other m 2021-02-23T09:31:04.51
IV.GAVE.EHE. ML:0.8 6.2450145E-5 0.1984 AML other m 2021-02-23T09:29:17.24
IV.GAVE.EHN. ML:0.8 6.533424E-5 0.16 AML other m 2021-02-23T09:29:18.92
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