Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.1 on date 23-10-2021 and time 04:39:31 (UTC) in region 4 km N Acquasanta Terme (AP)

A magnitude ML 1.1 earthquake occured in region: 4 km N Acquasanta Terme (AP), on

  • 23-10-2021 04:39:31 (UTC)
  • 23-10-2021 06:39:31 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 42.8070, 13.4020 at 19 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
Acquasanta Terme AP 4 2916 2916
Montegallo AP 7 523 3439
Roccafluvione AP 9 2010 5449
Arquata del Tronto AP 9 1178 6627
Venarotta AP 11 2066 8693
Valle Castellana TE 11 977 9670
Palmiano AP 11 196 9866
Montemonaco AP 12 604 10470
Ascoli Piceno AP 15 49407 59877
Montefortino FM 16 1178 61055
Comunanza AP 17 3166 64221
Rocca Santa Maria TE 17 537 64758
Accumoli RI 18 667 65425
Force AP 19 1354 66779
Folignano AP 19 9241 76020
Amandola FM 20 3629 79649

Municipalities with at least 50000 inhabitants

An earthquake occurred to
30 Km NW of Teramo (54892 inhabitants)
51 Km N of L'Aquila (69753 inhabitants)
59 Km E of Foligno (57155 inhabitants)
67 Km E of Terni (111501 inhabitants)
69 Km W of Montesilvano (53738 inhabitants)
77 Km NW of Pescara (121014 inhabitants)
81 Km NW of Chieti (51815 inhabitants)
89 Km E of Perugia (166134 inhabitants)
91 Km S 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 1.1 2021-10-23
04:39:31		 42.8073 13.4015 19 2021-10-23
04:47:28		 Sala Sismica INGV-Roma 96900221
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-10-23 04:39:31 ± 0.13
Latitude 42.8073 ± 0.0036
Longitude 13.4015 ± 0.0110
Depth (km) 19 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 96900221

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 888
Semi-minor axis of confidence ellipse (meter) 110
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 263
Circular confidence region, given by single value of horizontal uncertainty (meter) 890.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 152
Number of associated phases, regardless of their use for origin computation 25
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) 0.31836
Number of stations at which the event was observed 21
Number of stations from which data was used for origin computation 8
Magnitude information

ML:1.1

Field Value
Value 1.1
Uncertainty 0.3
Num. used stations 12
Type of magnitude ML
Reference to an origin 96900221
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-10-23 04:47:28
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.GIZZ.HHZ. 2021-10-23T04:41:28.46 3.0 undecidable manual Sn -2.97 0
IV.ECTS.HHZ. 2021-10-23T04:41:03.53 3.0 undecidable manual Pg 14.7 0
SL.LJU.BHZ. 2021-10-23T04:41:00.62 3.0 undecidable manual Sn -3.84 0
IV.MMGO.HHZ. 2021-10-23T04:40:56.69 3.0 positive manual Pg 6.67 0
IX.SCL3.EHZ.02 2021-10-23T04:40:48.43 3.0 undecidable manual Sn -0.19 0
IV.RESU.HHZ. 2021-10-23T04:40:47.08 3.0 undecidable manual Pn -3.15 0
IV.VBKN.HHZ. 2021-10-23T04:40:37.52 3.0 undecidable manual Sg 0.83 0
IV.ZEN8.EHZ. 2021-10-23T04:40:24.27 3.0 undecidable manual Pn -1.4 0
OT.OT17.EHZ. 2021-10-23T04:40:23.49 3.0 undecidable manual Sn -5.1 0
IV.SBPO.HNZ. 2021-10-23T04:40:21.62 3.0 negative manual Pg 3.36 0
IV.POFI.HHZ. 2021-10-23T04:40:07.27 3.0 undecidable manual S -5.25 0
IV.TST02.HHZ. 2021-10-23T04:39:52.35 3.0 negative manual P -1.01 0
IV.GUMA.HHE. 2021-10-23T04:39:42.57 0.6 undecidable manual S 349 28.8489 113 0.45 45
IV.SMA1.EHZ. 2021-10-23T04:39:40.27 0.6 undecidable manual S 195 20.3685 124 0.15 49
IV.SAP2.EHZ. 2021-10-23T04:39:40.64 3.0 undecidable manual S -0.57 0
IV.CSP1.EHZ. 2021-10-23T04:39:38.33 0.6 positive manual P 333 35.3424 108 -0.26 46
IV.MMO1.EHZ. 2021-10-23T04:39:38.35 0.6 undecidable manual S 329 11.877 142 -0.1 50
IV.GUMA.HHE. 2021-10-23T04:39:37.62 0.1 undecidable manual P 349 28.8489 113 -0.03 99
IV.TERO.HHZ. 2021-10-23T04:39:37.16 0.6 undecidable manual P 141 26.2515 116 -0.13 49
IV.MTRA.EHN. 2021-10-23T04:39:37.60 0.6 undecidable manual S 184 5.5944 160 -0.04 51
IV.NRCA.HHZ. 2021-10-23T04:39:36.92 0.1 positive manual P 277 23.5542 119 0 100
IV.SMA1.EHZ. 2021-10-23T04:39:36.59 0.3 positive manual P 195 20.3685 124 0.1 74
IV.MC2.EHZ. 2021-10-23T04:39:36.65 0.6 undecidable manual P 304 20.7681 123 0.1 49
IV.MTRA.EHN. 2021-10-23T04:39:35.01 0.3 undecidable manual P 184 5.5944 160 -0.05 77
IV.MMO1.EHZ. 2021-10-23T04:39:35.36 0.6 undecidable manual P 329 11.877 142 -0.17 49
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.SMA1.EHN. ML:0.9 0.00004685 0.26 AML other m 2021-10-23T04:39:40.59
IV.SMA1.EHE. ML:1.1 0.00006379999999999999 0.12 AML other m 2021-10-23T04:39:40.69
IV.NRCA.HHN. ML:0.8 0.00003655 0.52 AML other m 2021-10-23T04:39:41.46
IV.NRCA.HHE. ML:0.8 0.00003207615499999999 0.0992 AML other m 2021-10-23T04:39:42.31
IV.NRCA.HNE. ML:1.3 0.00010597672499999999 0.832 AML other m 2021-10-23T04:39:45.71
IV.NRCA.HNN. ML:1.5 0.0001805612 0.7808 AML other m 2021-10-23T04:39:51.61
IV.TERO.HHE. ML:1.1 0.000063188385 0.2624 AML other m 2021-10-23T04:39:44.45
IV.TERO.HHN. ML:0.3 0.000010307098500000001 0.08 AML other m 2021-10-23T04:39:42.83
IV.TERO.HNE. ML:1.4 0.00010719824999999999 1.0304 AML other m 2021-10-23T04:39:37.22
IV.TERO.HNN. ML:1.7 0.00021551575 1.2512 AML other m 2021-10-23T04:39:50.58
IV.CSP1.EHE. ML:1.3 0.00007057251000000001 1.7792 AML other m 2021-10-23T04:39:42.91
IV.CSP1.EHN. ML:1.2 0.0000607644 1.3984 AML other m 2021-10-23T04:39:51.34
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