Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.3 on date 20-09-2021 and time 17:54:38 (Italy) in region 4 km E Norcia (PG)

A magnitude ML 1.3 earthquake occured in region: 4 km E Norcia (PG), on

  • 20-09-2021 15:54:38 (UTC)
  • 20-09-2021 17:54:38 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 42.7850, 13.1380 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
Norcia PG 4 4957 4957
Castelsantangelo sul Nera MC 12 281 5238
Cascia PG 13 3217 8455
Arquata del Tronto AP 13 1178 9633
Preci PG 13 724 10357
Accumoli RI 13 667 11024
Visso MC 17 1107 12131
Montegallo AP 17 523 12654
Ussita MC 18 444 13098
Poggiodomo PG 18 117 13215
Cerreto di Spoleto PG 18 1075 14290
Cittareale RI 19 482 14772

Municipalities with at least 50000 inhabitants

An earthquake occurred to
40 Km E of Foligno (57155 inhabitants)
47 Km NE of Terni (111501 inhabitants)
48 Km W of Teramo (54892 inhabitants)
53 Km NW of L'Aquila (69753 inhabitants)
71 Km SE of Perugia (166134 inhabitants)
88 Km W of Montesilvano (53738 inhabitants)
93 Km NE of Guidonia Montecelio (88673 inhabitants)
94 Km E of Viterbo (67173 inhabitants)
95 Km W of Pescara (121014 inhabitants)
95 Km N of Tivoli (56533 inhabitants)
97 Km NW of Chieti (51815 inhabitants)
98 Km SW of Ancona (100861 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 1.3 2021-09-20
15:54:38		 42.7848 13.138 11 2021-09-20
15:59:03		 Sala Sismica INGV-Roma 95668731
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-09-20 15:54:38 ± 0.03
Latitude 42.7848 ± 0.0009
Longitude 13.1380 ± 0.0037
Depth (km) 11 ± 0 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 95668731

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 250
Semi-minor axis of confidence ellipse (meter) 66
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 268
Circular confidence region, given by single value of horizontal uncertainty (meter) 250.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 99
Number of associated phases, regardless of their use for origin computation 17
Number of defining phases 17
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.08
Epicentral distance of station closest to the epicenter (degree) 0.05126
Epicentral distance of station farthest from the epicenter (degree) 0.37861
Number of stations at which the event was observed 9
Number of stations from which data was used for origin computation 9
Magnitude information

ML:1.3

Field Value
Value 1.3
Uncertainty 0.4
Num. used stations 4
Type of magnitude ML
Reference to an origin 95668731
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-09-20 15:59:03
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.CSP1.EHZ. 2021-09-20T15:54:49.93 0.6 undecidable manual S 9 34.4433 50 0.07 48
IV.CESI.HHZ. 2021-09-20T15:54:48.80 0.6 undecidable manual S 322 30.9468 50 -0.11 48
IV.FDMO.HHN. 2021-09-20T15:54:48.10 0.6 undecidable manual S 352 28.2495 50 -0.09 48
IV.T1299.HNE. 2021-09-20T15:54:46.13 0.6 undecidable manual S 145 20.4684 50 0.01 50
IV.TERO.HHZ. 2021-09-20T15:54:46.04 0.6 undecidable manual P 115 42.0246 50 -0.06 47
IV.GAVE.EHZ. 2021-09-20T15:54:46.77 0.6 undecidable manual S 243 22.3554 50 0.14 48
IV.LNSS.HHE. 2021-09-20T15:54:46.47 0.6 undecidable manual S 202 21.6672 50 0.01 50
IV.CSP1.EHZ. 2021-09-20T15:54:44.86 1.0 positive manual P 9 34.4433 50 -0.07 24
IV.CESI.HHZ. 2021-09-20T15:54:44.28 0.1 undecidable manual P 322 30.9468 50 -0.1 96
IV.MC2.EHZ. 2021-09-20T15:54:44.74 0.6 undecidable manual S 16 14.6742 50 0.17 49
IV.GAVE.EHZ. 2021-09-20T15:54:43.13 0.6 negative manual P 243 22.3554 50 0.06 49
IV.FDMO.HHN. 2021-09-20T15:54:43.96 0.1 undecidable manual P 352 28.2495 50 -0.01 98
IV.NRCA.HHZ. 2021-09-20T15:54:42.41 0.6 undecidable manual S 340 5.6943 153 -0.11 50
IV.LNSS.HHE. 2021-09-20T15:54:42.94 0.1 undecidable manual P 202 21.6672 50 -0.02 99
IV.T1299.HNE. 2021-09-20T15:54:42.70 0.1 undecidable manual P 145 20.4684 50 -0.07 98
IV.MC2.EHZ. 2021-09-20T15:54:41.96 0.6 negative manual P 16 14.6742 50 0.09 49
IV.NRCA.HHZ. 2021-09-20T15:54:40.81 0.1 undecidable manual P 340 5.6943 153 0.11 100
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.NRCA.HHE. ML:1.6 0.000675 0.16 AML other m 2021-09-20T15:54:42.45
IV.NRCA.HHN. ML:1.5 0.000524 0.7 AML other m 2021-09-20T15:54:42.84
IV.GAVE.EHE. ML:1.0 0.00005955 0.5 AML other m 2021-09-20T15:54:47.12
IV.GAVE.EHN. ML:0.9 0.000047799999999999996 0.78 AML other m 2021-09-20T15:54:48.18
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