Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.2 on date 15-08-2021 and time 03:37:37 (UTC) in region 4 km W Riolo Terme (RA)

A magnitude ML 1.2 earthquake occured in region: 4 km W Riolo Terme (RA), on

  • 15-08-2021 03:37:37 (UTC)
  • 15-08-2021 05:37:37 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 44.2840, 11.6730 at 17 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
Riolo Terme RA 4 5720 5720
Casalfiumanese BO 5 3438 9158
Borgo Tossignano BO 7 3288 12446
Casola Valsenio RA 8 2617 15063
Imola BO 8 69797 84860
Dozza BO 9 6652 91512
Fontanelice BO 10 1943 93455
Brisighella RA 10 7639 101094
Castel Bolognese RA 11 9554 110648
Castel San Pietro Terme BO 14 20811 131459
Castel del Rio BO 16 1246 132705
Solarolo RA 16 4488 137193
Castel Guelfo di Bologna BO 17 4455 141648
Faenza RA 17 58541 200189
Mordano BO 17 4760 204949
Bagnara di Romagna RA 17 2429 207378
Modigliana FC 17 4560 211938

Municipalities with at least 50000 inhabitants

An earthquake occurred to
8 Km SW of Imola (69797 inhabitants)
17 Km W of Faenza (58541 inhabitants)
30 Km W of Forlì (117913 inhabitants)
35 Km SE of Bologna (386663 inhabitants)
45 Km W of Ravenna (159116 inhabitants)
48 Km W of Cesena (96758 inhabitants)
62 Km S of Ferrara (133155 inhabitants)
64 Km NE of Prato (191150 inhabitants)
66 Km NE of Firenze (382808 inhabitants)
70 Km NE of Scandicci (50609 inhabitants)
72 Km SE of Modena (184973 inhabitants)
72 Km NE of Pistoia (90315 inhabitants)
75 Km W of Rimini (147750 inhabitants)
84 Km SE of Carpi (70699 inhabitants)
88 Km S of Rovigo (51867 inhabitants)
92 Km N of Arezzo (99543 inhabitants)
95 Km E of Reggio nell'Emilia (171345 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 1.2 2021-08-15
03:37:37		 44.2842 11.6733 17 2021-12-29
11:12:33		 Bollettino Sismico Italiano INGV 95949451
Reviewed
Rev100 		ML 1.1 2021-08-15
03:37:38		 44.2475 11.6725 10 2021-08-15
04:10:16		 Sala Sismica INGV-Roma 94177101
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-08-15 03:37:37 ± 0.37
Latitude 44.2842 ± 0.0153
Longitude 11.6733 ± 0.0176
Depth (km) 17 ± 3 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-INGV
Event type earthquake
Origin ID 95949451

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 1351
Semi-minor axis of confidence ellipse (meter) 1258
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 236
Circular confidence region, given by single value of horizontal uncertainty (meter) 1350.0
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 19
Number of defining phases 18
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.44
Epicentral distance of station closest to the epicenter (degree) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.69428
Number of stations at which the event was observed 10
Number of stations from which data was used for origin computation 9
Magnitudes information

ML:1.2

Field Value
Value 1.2
Uncertainty 0.3
Num. used stations 16
Type of magnitude ML
Reference to an origin 95949451
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2021-09-27 14:52:54

ML:1.1

Field Value
Value 1.1
Uncertainty 0.3
Num. used stations 16
Type of magnitude ML
Reference to an origin 94177101
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-08-15 04:10:16
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.GSCL.HHZ. 2021-08-15T03:38:03.20 3.0 undecidable manual P 0
IV.CRE.HHZ. 2021-08-15T03:38:02.17 0.6 undecidable manual S 163 77.0673 95 1.31 28
IV.ASQU.HHZ. 2021-08-15T03:37:55.49 0.6 undecidable manual S 170 54.9006 98 0.52 42
IV.BOSL.HHZ. 2021-08-15T03:37:53.00 0.6 undecidable manual S 211 45.8208 100 0.41 44
IV.SFI.EHZ. 2021-08-15T03:37:52.57 0.3 undecidable manual S 162 44.3223 100 0.39 68
IV.CRE.HHZ. 2021-08-15T03:37:51.58 0.3 undecidable manual P 163 77.0673 95 0.48 62
IV.ASQU.HHZ. 2021-08-15T03:37:47.40 0.3 undecidable manual P 170 54.9006 98 -0.29 68
IV.MTRZ.HHZ. 2021-08-15T03:37:46.79 0.6 undecidable manual S 279 19.9689 120 0.77 41
IV.VISG.HHZ. 2021-08-15T03:37:46.04 0.6 undecidable manual S 241 21.7671 117 -0.39 47
IV.LMD.HHZ. 2021-08-15T03:37:46.47 0.3 undecidable manual S 173 23.0547 115 -0.28 72
IV.BOSL.HHZ. 2021-08-15T03:37:45.99 0.3 undecidable manual P 211 45.8208 100 -0.33 69
IV.SFI.EHZ. 2021-08-15T03:37:45.57 0.3 undecidable manual P 162 44.3223 100 -0.52 66
IV.BRIS.HHZ. 2021-08-15T03:37:44.13 0.3 undecidable manual S 132 9.9789 144 0.13 77
IV.IMOL.EHZ. 2021-08-15T03:37:44.80 0.3 undecidable manual S 33 9.9789 143 0.79 65
IV.VISG.HHZ. 2021-08-15T03:37:42.19 0.1 undecidable manual P 241 21.7671 117 -0.57 90
IV.LMD.HHZ. 2021-08-15T03:37:42.36 0.1 undecidable manual P 173 23.0547 115 -0.59 89
IV.MTRZ.HHZ. 2021-08-15T03:37:42.94 0.1 undecidable manual P 279 19.9689 120 0.41 94
IV.BRIS.HHZ. 2021-08-15T03:37:41.03 0.1 undecidable manual P 132 9.9789 144 -0.33 96
IV.IMOL.EHZ. 2021-08-15T03:37:41.23 0.1 undecidable manual P 33 9.9789 143 -0.14 100
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
IV.BRIS.HHE. ML:1.5 0.000286 0.56 AML other m 2021-08-15T03:37:44.48
IV.IMOL.HNN. ML:1.9 0.000748 0.16 AML other m 2021-08-15T03:37:45.35
IV.IMOL.HNE. ML:1.9 0.0007005000000000001 0.68 AML other m 2021-08-15T03:37:46.34
IV.BRIS.HHN. ML:1.3 0.00017999999999999998 0.32 AML other m 2021-08-15T03:37:46.75
IV.VISG.HHE. ML:1.1 0.0000767 0.1 AML other m 2021-08-15T03:37:47.42
IV.LMD.HHN. ML:1.4 0.0001265 0.16 AML other m 2021-08-15T03:37:47.71
IV.VISG.HHN. ML:1.1 0.00007315 1.88 AML other m 2021-08-15T03:37:47.94
IV.LMD.HHE. ML:1.1 0.00007039999999999999 0.14 AML other m 2021-08-15T03:37:48.17
IV.MTRZ.HHN. ML:1.3 0.00011 0.5 AML other m 2021-08-15T03:37:48.65
IV.BOSL.HHE. ML:0.6 0.000008845000000000001 0.46 AML other m 2021-08-15T03:37:48.75
IV.MTRZ.HHE. ML:1.4 0.000156 0.32 AML other m 2021-08-15T03:37:49.09
IV.SFI.EHN. ML:1.1 0.000034699999999999996 0.12 AML other m 2021-08-15T03:37:53.34
IV.SFI.EHE. ML:1.1 0.000037900000000000006 0.56 AML other m 2021-08-15T03:37:54.68
IV.BOSL.HHN. ML:0.6 0.000011425 0.38 AML other m 2021-08-15T03:37:56.64
IV.ASQU.HHE. ML:1.1 0.00002775 0.24 AML other m 2021-08-15T03:37:57.35
IV.ASQU.HHN. ML:1.0 0.0000205 0.46 AML other m 2021-08-15T03:37:57.38
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