Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 0.9 on date 31-10-2021 and time 10:40:44 (UTC) in region 4 km E Massa Martana (PG)

A magnitude ML 0.9 earthquake occured in region: 4 km E Massa Martana (PG), on

  • 31-10-2021 10:40:44 (UTC)
  • 31-10-2021 11:40:44 (UTC +01:00) Italian time

and geographic coordinates (lat, lon) 42.7940, 12.5680 at 5 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
Massa Martana PG 4 3770 3770
Giano dell'Umbria PG 5 3846 7616
Castel Ritaldi PG 9 3278 10894
Acquasparta TR 12 4778 15672
Gualdo Cattaneo PG 13 6155 21827
Todi PG 13 16851 38678
Montefalco PG 13 5679 44357
Spoleto PG 15 38218 82575
Collazzone PG 15 3473 86048
Bevagna PG 16 5081 91129
Montecastrilli TR 17 5022 96151
Trevi PG 17 8469 104620
Campello sul Clitunno PG 17 2442 107062
Fratta Todina PG 18 1839 108901
Monte Castello di Vibio PG 18 1567 110468
Avigliano Umbro TR 19 2558 113026
San Gemini TR 20 5018 118044

Municipalities with at least 50000 inhabitants

An earthquake occurred to
21 Km SW of Foligno (57155 inhabitants)
27 Km N of Terni (111501 inhabitants)
38 Km SE of Perugia (166134 inhabitants)
56 Km NE of Viterbo (67173 inhabitants)
84 Km NW of L'Aquila (69753 inhabitants)
89 Km N of Guidonia Montecelio (88673 inhabitants)
93 Km SE of Arezzo (99543 inhabitants)
94 Km N of Tivoli (56533 inhabitants)
94 Km W of Teramo (54892 inhabitants)
100 Km N of Roma (2864731 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 0.9 2021-10-31
10:40:44		 42.7938 12.5683 5 2022-03-30
13:04:38		 Bollettino Sismico Italiano INGV 101080451
Reviewed
Rev100 		ML 1.0 2021-10-31
10:40:43		 42.7187 12.6008 10 2021-10-31
10:48:09		 Sala Sismica INGV-Roma 97109381
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-10-31 10:40:44 ± 0.12
Latitude 42.7938 ± 0.0054
Longitude 12.5683 ± 0.0074
Depth (km) 5 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-INGV
Event type earthquake
Origin ID 101080451

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 600
Semi-minor axis of confidence ellipse (meter) 447
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 344
Circular confidence region, given by single value of horizontal uncertainty (meter) 600.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 114
Number of associated phases, regardless of their use for origin computation 38
Number of defining phases 18
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.29
Epicentral distance of station closest to the epicenter (degree) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.55308
Number of stations at which the event was observed 27
Number of stations from which data was used for origin computation 9
Magnitudes information

ML:0.9

Field Value
Value 0.9
Uncertainty 0.2
Num. used stations 4
Type of magnitude ML
Reference to an origin 101080451
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2022-02-17 12:08:03

ML:1.0

Field Value
Value 1.0
Uncertainty 0.2
Num. used stations 4
Type of magnitude ML
Reference to an origin 97109381
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-10-31 10:48:09
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.DGI.HHZ. 2021-10-31T10:42:33.22 3.0 undecidable manual Sg 14.74 0
IV.PTCC.HHZ. 2021-10-31T10:42:32.06 3.0 undecidable manual Sg 9.89 0
GU.CANO.HHZ. 2021-10-31T10:42:29.84 3.0 undecidable manual Sn 8.62 0
IV.RESU.HHZ. 2021-10-31T10:42:20.62 3.0 undecidable manual Pg 18.889999 0
IV.CROCE.HHZ. 2021-10-31T10:42:13.70 3.0 positive manual Pn -0.01 0
IV.TEOL.HHZ. 2021-10-31T10:41:56.76 3.0 undecidable manual Sn -2.07 0
IV.PLMA.HHZ. 2021-10-31T10:41:54.75 3.0 undecidable manual Sn 0.99 0
OT.OT17.EHZ. 2021-10-31T10:41:52.48 3.0 undecidable manual Sn 3.08 0
IV.PTCC.HHZ. 2021-10-31T10:41:42.65 3.0 undecidable manual Pn 3.96 0
IV.AGLI.HHZ. 2021-10-31T10:41:41.89 3.0 undecidable manual Pg 9.12 0
IV.FREG.EHZ. 2021-10-31T10:41:41.06 3.0 undecidable manual Pg 7.95 0
IV.ZEN8.EHZ. 2021-10-31T10:41:36.89 3.0 undecidable manual Pn 4.27 0
IV.BOZZ.HNZ. 2021-10-31T10:41:31.68 3.0 positive manual Pn 3.93 0
IV.RNI2.HHZ. 2021-10-31T10:41:31.02 3.0 undecidable manual S -0.77 0
IV.RIBO.EHZ.01 2021-10-31T10:41:25.27 3.0 undecidable manual S 0.28 0
OT.OT17.EHZ. 2021-10-31T10:41:22.46 3.0 negative manual Pn 2.18 0
IV.PE3.EHZ. 2021-10-31T10:41:12.41 3.0 undecidable manual S -1.96 0
IV.CERA.HHZ. 2021-10-31T10:41:10.36 3.0 negative manual P -0.26 0
IV.PP3.EHZ. 2021-10-31T10:41:10.34 3.0 undecidable manual S -2.37 0
IV.CSP1.EHZ. 2021-10-31T10:41:05.22 0.3 undecidable manual S 57 61.3941 50 0.16 66
IV.VIVA.HHZ. 2021-10-31T10:41:02.95 3.0 positive manual P -1.22 0
IV.NRCA.HHZ. 2021-10-31T10:41:00.49 0.6 undecidable manual S 84 44.622 96 0.03 47
IV.MGAB.HHZ. 2021-10-31T10:40:59.05 0.6 undecidable manual S 290 39.4272 97 0.41 44
IV.CESI.HHE. 2021-10-31T10:40:57.68 0.6 undecidable manual S 49 35.9418 98 0.2 46
IV.CSP1.EHZ. 2021-10-31T10:40:56.10 0.3 undecidable manual P 57 61.3941 50 -0.43 63
IV.ASSB.HHZ. 2021-10-31T10:40:55.32 0.3 undecidable manual S 15 28.5492 100 0.39 67
IV.GAVE.HNZ. 2021-10-31T10:40:55.87 0.6 undecidable manual S 113 28.8489 100 0.85 38
IV.NRCA.HHZ. 2021-10-31T10:40:53.11 0.3 undecidable manual P 84 44.622 96 -0.76 57
IV.CESX.HHZ. 2021-10-31T10:40:52.02 0.6 undecidable manual S 176 20.5683 104 -0.21 47
IV.MGAB.HHZ. 2021-10-31T10:40:52.74 0.3 undecidable manual P 290 39.4272 97 -0.09 70
IV.CESI.HHE. 2021-10-31T10:40:51.82 0.3 undecidable manual P 49 35.9418 98 -0.33 67
IV.GAVE.HNZ. 2021-10-31T10:40:50.99 0.3 undecidable manual P 113 28.8489 100 0.26 69
IV.ASSB.HHZ. 2021-10-31T10:40:50.50 0.3 undecidable manual P 15 28.5492 100 -0.18 70
IV.CESX.HHZ. 2021-10-31T10:40:49.28 0.3 undecidable manual P 176 20.5683 104 0.16 71
IV.MOMA.HHZ. 2021-10-31T10:40:46.48 0.6 undecidable manual S 7 1.0989 167 -0.15 49
IT.GNU.HGZ. 2021-10-31T10:40:46.36 0.6 undecidable manual S 7 1.0989 167 -0.27 48
IV.MOMA.HHZ. 2021-10-31T10:40:45.97 0.1 undecidable manual P 7 1.0989 167 0.08 100
IT.GNU.HGZ. 2021-10-31T10:40:45.96 0.1 undecidable manual P 7 1.0989 167 0.07 100
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.ASSB.HHN. ML:0.8 0.00003235000000000001 0.5 AML other m 2021-10-31T10:40:56.61
IV.ASSB.HHE. ML:0.8 0.00003685 0.34 AML other m 2021-10-31T10:40:57.31
IV.MGAB.HHN. ML:1.1 0.00004965 0.18 AML other m 2021-10-31T10:41:00.58
IV.MGAB.HHE. ML:0.9 0.0000305 0.44 AML other m 2021-10-31T10:41:02.75
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