Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.8 on date 09-08-2021 and time 12:38:25 (Italy) in region 4 km NW Petralia Sottana (PA)

A magnitude ML 1.8 earthquake occured in region: 4 km NW Petralia Sottana (PA), on

  • 09-08-2021 10:38:25 (UTC)
  • 09-08-2021 12:38:25 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 37.8330, 14.0660 at 9 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
Petralia Sottana PA 4 2821 2821
Petralia Soprana PA 6 3360 6181
Castellana Sicula PA 6 3411 9592
Polizzi Generosa PA 6 3407 12999
Geraci Siculo PA 8 1945 14944
Blufi PA 9 1029 15973
Bompietro PA 10 1401 17374
Castelbuono PA 12 8943 26317
Gangi PA 13 6811 33128
Isnello PA 14 1589 34717
Scillato PA 14 613 35330
San Mauro Castelverde PA 14 1701 37031
Collesano PA 15 4054 41085
Caltavuturo PA 16 4017 45102
Alimena PA 16 2032 47134
Gratteri PA 17 963 48097
Resuttano CL 17 2038 50135
Sclafani Bagni PA 19 426 50561
Pollina PA 19 2974 53535

Municipalities with at least 50000 inhabitants

An earthquake occurred to
38 Km N of Caltanissetta (63360 inhabitants)
56 Km SE of Bagheria (55387 inhabitants)
69 Km E of Palermo (674435 inhabitants)
72 Km NE of Agrigento (59770 inhabitants)
87 Km N of Gela (75827 inhabitants)
97 Km W of Catania (314555 inhabitants)
100 Km W of Acireale (52622 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 1.8 2021-08-09
10:38:25		 37.8333 14.0662 9 2021-12-29
11:12:30		 Bollettino Sismico Italiano INGV 95412621
Reviewed
Rev100 		ML 1.8 2021-08-09
10:38:25		 37.8185 14.0555 9 2021-08-09
10:46:44		 Sala Sismica INGV-Roma 93879391
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-08-09 10:38:25 ± 0.09
Latitude 37.8333 ± 0.0045
Longitude 14.0662 ± 0.0080
Depth (km) 9 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-INGV
Event type earthquake
Origin ID 95412621

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 670
Semi-minor axis of confidence ellipse (meter) 305
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 95
Circular confidence region, given by single value of horizontal uncertainty (meter) 670.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 60
Number of associated phases, regardless of their use for origin computation 19
Number of defining phases 19
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.26
Epicentral distance of station closest to the epicenter (degree) 0.03867
Epicentral distance of station farthest from the epicenter (degree) 0.66999
Number of stations at which the event was observed 13
Number of stations from which data was used for origin computation 13
Magnitudes information

ML:1.8

Field Value
Value 1.8
Uncertainty 0.2
Num. used stations 18
Type of magnitude ML
Reference to an origin 95412621
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2021-09-14 07:57:41

ML:1.8

Field Value
Value 1.8
Uncertainty 0.2
Num. used stations 16
Type of magnitude ML
Reference to an origin 93879391
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-08-09 10:46:44
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.MUCR.HHZ. 2021-08-09T10:38:39.09 0.6 undecidable manual P 72 74.37 50 0.46 41
IV.ALJA.HHZ. 2021-08-09T10:38:36.40 0.6 undecidable manual S 251 28.9488 50 0.31 45
IV.MCPD.HHZ. 2021-08-09T10:38:36.67 0.6 undecidable manual P 61 66.2781 50 -0.7 37
IV.SOLUN.HHE. 2021-08-09T10:38:35.68 0.6 undecidable manual P 302 54.8007 50 0.07 46
IV.GALF.HHE. 2021-08-09T10:38:34.66 0.6 undecidable manual P 107 45.9207 50 0.42 44
IV.CAGR.HHE. 2021-08-09T10:38:34.26 0.6 undecidable manual P 122 44.7219 50 0.21 46
IV.CMDO.HHE. 2021-08-09T10:38:34.76 0.6 undecidable manual P 208 46.2204 50 0.47 43
IV.RESU.HHZ. 2021-08-09T10:38:33.70 0.6 undecidable manual S 182 20.6682 114 0.28 47
IV.GIB.HHZ. 2021-08-09T10:38:32.83 0.3 undecidable manual S 349 17.7711 118 0.33 70
IV.PLLN.EHZ. 2021-08-09T10:38:32.80 0.3 undecidable manual S 21 18.87 116 -0.06 73
IV.SCIAR.HHZ. 2021-08-09T10:38:31.36 0.6 undecidable manual P 293 30.1476 50 -0.46 44
IV.ALJA.HHZ. 2021-08-09T10:38:31.41 0.3 undecidable manual P 251 28.9488 50 -0.22 70
IV.CSLB.HHZ. 2021-08-09T10:38:30.90 0.3 undecidable manual S 356 11.5773 129 0.19 72
IV.PLLN.EHZ. 2021-08-09T10:38:29.41 0.6 undecidable manual P 21 18.87 116 -0.35 46
IV.PETRA.HHZ. 2021-08-09T10:38:29.20 0.3 undecidable manual S 90 4.2957 156 0.09 75
IV.RESU.HHZ. 2021-08-09T10:38:29.54 0.3 undecidable manual P 182 20.6682 114 -0.55 66
IV.GIB.HHZ. 2021-08-09T10:38:29.47 0.1 undecidable manual P 349 17.7711 118 -0.09 98
IV.CSLB.HHZ. 2021-08-09T10:38:28.46 0.1 undecidable manual P 356 11.5773 129 -0.06 99
IV.PETRA.HHZ. 2021-08-09T10:38:27.51 0.1 positive manual P 90 4.2957 156 -0.09 100
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.PETRA.HHN. ML:2.4 0.00430773 0.256 AML other m 2021-08-09T10:38:29.51
IV.PETRA.HHE. ML:2.1 0.0025341045 0.1984 AML other m 2021-08-09T10:38:29.65
IV.CSLB.HHE. ML:1.8 0.0007239999999999999 0.36 AML other m 2021-08-09T10:38:32.58
IV.CSLB.HHN. ML:1.6 0.00047329825 0.2432 AML other m 2021-08-09T10:38:32.64
IV.RESU.HHN. ML:2.1 0.0008895000000000001 0.32 AML other m 2021-08-09T10:38:35.79
IV.RESU.HHE. ML:1.8 0.000479 0.36 AML other m 2021-08-09T10:38:35.65
IV.GIB.HHN. ML:1.8 0.0006475 1.3 AML other m 2021-08-09T10:38:36.71
IV.GIB.HHE. ML:1.8 0.00048450000000000007 0.38 AML other m 2021-08-09T10:38:36.72
IV.PLLN.EHN. ML:1.6 0.000357 0.46 AML other m 2021-08-09T10:38:38.12
IV.SCIAR.HHN. ML:1.5 0.00016350000000000002 0.28 AML other m 2021-08-09T10:38:38.65
IV.PLLN.EHE. ML:1.6 0.0003165 0.7 AML other m 2021-08-09T10:38:38.70
IV.SCIAR.HHE. ML:1.6 0.0002062213 0.384 AML other m 2021-08-09T10:38:38.01
IV.ALJA.HHN. ML:1.6 0.0002205743 0.256 AML other m 2021-08-09T10:38:39.62
IV.ALJA.HHE. ML:1.9 0.0003749991 0.2432 AML other m 2021-08-09T10:38:39.62
IV.MUCR.HHN. ML:1.7 0.00008199999999999999 1.48 AML other m 2021-08-09T10:38:53.81
IV.MUCR.HHE. ML:1.6 0.000053847365 0.3008 AML other m 2021-08-09T10:38:55.13
IV.SCIAR.HNN. ML:1.8 0.00029166205 0.3904 AML other m 2021-08-09T10:38:37.97
IV.SCIAR.HNE. ML:1.6 0.00018756040000000003 0.2752 AML other m 2021-08-09T10:38:38.60
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