Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.0 on date 17-04-2021 and time 20:15:54 (Italy) in region 3 km W Montefranco (TR)

A magnitude ML 1.0 earthquake occured in region: 3 km W Montefranco (TR), on

  • 17-04-2021 18:15:54 (UTC)
  • 17-04-2021 20:15:54 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 42.6020, 12.7250 at 8 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
Montefranco TR 4 1276 1276
Arrone TR 4 2763 4039
Ferentillo TR 6 1913 5952
Terni TR 8 111501 117453
Polino TR 10 233 117686
Labro RI 10 374 118060
Colli sul Velino RI 12 533 118593
Morro Reatino RI 12 373 118966
Stroncone TR 13 4917 123883
Rivodutri RI 14 1253 125136
San Gemini TR 15 5018 130154
Spoleto PG 15 38218 168372
Scheggino PG 15 461 168833
Greccio RI 17 1558 170391
Poggio Bustone RI 17 2055 172446
Sant'Anatolia di Narco PG 17 564 173010
Acquasparta TR 18 4778 177788
Narni TR 19 19785 197573
Monteleone di Spoleto PG 19 599 198172

Municipalities with at least 50000 inhabitants

An earthquake occurred to
8 Km NE of Terni (111501 inhabitants)
40 Km S of Foligno (57155 inhabitants)
55 Km E of Viterbo (67173 inhabitants)
62 Km W of L'Aquila (69753 inhabitants)
63 Km SE of Perugia (166134 inhabitants)
67 Km N of Guidonia Montecelio (88673 inhabitants)
71 Km N of Tivoli (56533 inhabitants)
80 Km W of Teramo (54892 inhabitants)
81 Km N of Roma (2864731 inhabitants)
95 Km NE of Civitavecchia (52991 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 2021-04-17
18:15:54		 42.6022 12.7253 9 2021-04-17
18:43:40		 Sala Sismica INGV-Roma 89185901
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-04-17 18:15:54 ± 0.08
Latitude 42.6022 ± 0.0045
Longitude 12.7253 ± 0.0037
Depth (km) 9 ± 0 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 89185901

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 507
Semi-minor axis of confidence ellipse (meter) 173
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 199
Circular confidence region, given by single value of horizontal uncertainty (meter) 510.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 146
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) 0.15
Epicentral distance of station closest to the epicenter (degree) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.37232
Number of stations at which the event was observed 7
Number of stations from which data was used for origin computation 6
Magnitude information

ML:1.0

Field Value
Value 1.0
Uncertainty 0.1
Num. used stations 10
Type of magnitude ML
Reference to an origin 89185901
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-04-17 18:43:40
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.SRES.HHZ. 2021-04-17T18:16:09.51 3.0 undecidable manual S 0 0
IV.RM33.EHZ. 2021-04-17T18:16:08.44 0.3 undecidable manual S 104 41.3253 50 -0.01 73
IV.MOMA.HHZ. 2021-04-17T18:16:03.76 0.6 undecidable manual S 331 25.6521 108 -0.03 50
IV.LNSS.HHZ. 2021-04-17T18:16:03.85 0.3 undecidable manual S 90 25.752 108 0.06 74
IV.RM33.EHZ. 2021-04-17T18:16:02.32 0.6 undecidable manual P 104 41.3253 50 -0.19 47
IV.GAVE.EHZ. 2021-04-17T18:16:00.94 0.3 undecidable manual S 54 16.9719 117 -0.06 76
IV.LNSS.HHZ. 2021-04-17T18:15:59.80 0.1 undecidable manual P 90 25.752 108 -0.03 100
IV.CESX.HHZ. 2021-04-17T18:15:59.23 0.3 undecidable manual S 274 11.3775 127 -0.09 76
IV.MOMA.HHZ. 2021-04-17T18:15:59.77 0.1 undecidable manual P 331 25.6521 108 -0.05 99
IV.GAVE.EHZ. 2021-04-17T18:15:58.37 0.3 positive manual P 54 16.9719 117 0.16 74
IV.ARRO.EHZ. 2021-04-17T18:15:57.46 0.3 undecidable manual S 128 4.1958 154 -0.22 75
IV.CESX.HHZ. 2021-04-17T18:15:57.71 1.0 negative manual P 274 11.3775 127 0.47 23
IV.ARRO.EHZ. 2021-04-17T18:15:56.49 0.1 undecidable manual P 128 4.1958 154 0.2 100
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.CESX.HHN. ML:1.0 0.000129 1.38 AML other m 2021-04-17T18:16:01.10
IV.CESX.HHE. ML:1.0 0.000131 1.3 AML other m 2021-04-17T18:16:02.77
IV.GAVE.EHN. ML:1.0 0.00008724999999999999 0.3 AML other m 2021-04-17T18:16:03.44
IV.GAVE.EHE. ML:1.1 0.00011899999999999999 0.78 AML other m 2021-04-17T18:16:03.21
IV.MOMA.HHN. ML:0.8 0.00004149999999999999 1.3 AML other m 2021-04-17T18:16:04.87
IV.LNSS.HHN. ML:1.2 0.00010175 0.76 AML other m 2021-04-17T18:16:04.90
IV.LNSS.HHE. ML:1.2 0.0000899 0.48 AML other m 2021-04-17T18:16:05.47
IV.MOMA.HHE. ML:0.9 0.00005165 0.14 AML other m 2021-04-17T18:16:05.47
IV.RM33.EHN. ML:1.0 0.000033549999999999996 0.68 AML other m 2021-04-17T18:16:12.34
IV.RM33.EHE. ML:1.0 0.00003585 0.54 AML other m 2021-04-17T18:16:12.77
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