Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of ML 1.0 on date 28-07-2021 and time 13:57:42 (Italy) in region Costa Ligure Occidentale (Imperia)

A magnitude ML 1.0 earthquake occured in region: Costa Ligure Occidentale (Imperia), on

  • 28-07-2021 11:57:42 (UTC)
  • 28-07-2021 13:57:42 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 43.8790, 7.4440 at 10 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
Olivetta San Michele IM 6 211 211
Airole IM 9 407 618
Rocchetta Nervina IM 13 298 916
Dolceacqua IM 15 2074 2990
Isolabona IM 16 679 3669
Camporosso IM 16 5632 9301
Ventimiglia IM 17 24310 33611
Apricale IM 17 629 34240
Soldano IM 18 977 35217
San Biagio della Cima IM 18 1329 36546
Perinaldo IM 19 870 37416
Vallecrosia IM 19 6956 44372
Pigna IM 19 859 45231
Vallebona IM 19 1310 46541
Castel Vittorio IM 19 287 46828

Municipalities with at least 50000 inhabitants

An earthquake occurred to
28 Km W of Sanremo (54807 inhabitants)
58 Km S of Cuneo (56081 inhabitants)
96 Km W of Savona (61345 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 1.0 2021-07-28
11:57:42		 43.879 7.4443 10 2021-12-29
11:12:27		 Bollettino Sismico Italiano INGV 95148341
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-07-28 11:57:42 ± 0.1
Latitude 43.8790 ± 0.0045
Longitude 7.4443 ± 0.0075
Depth (km) 10 ± 0 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-INGV
Event type earthquake
Origin ID 95148341

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 591
Semi-minor axis of confidence ellipse (meter) 411
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 247
Circular confidence region, given by single value of horizontal uncertainty (meter) 590.0
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 200
Number of associated phases, regardless of their use for origin computation 12
Number of defining phases 12
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.16
Epicentral distance of station closest to the epicenter (degree) 0.12591
Epicentral distance of station farthest from the epicenter (degree) 0.66999
Number of stations at which the event was observed 7
Number of stations from which data was used for origin computation 7
Magnitude information

ML:1.0

Field Value
Value 1.0
Uncertainty 0.2
Num. used stations 10
Type of magnitude ML
Reference to an origin 95148341
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2021-09-07 09:30:52
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
GU.GBOS.HHZ. 2021-07-28T11:57:58.65 0.3 undecidable manual S 38 51.1155 50 -0.24 67
GU.PZZ.HHZ. 2021-07-28T11:57:55.63 0.1 undecidable manual P 340 74.37 50 0.05 89
GU.IMI.HHZ. 2021-07-28T11:57:54.80 0.1 undecidable manual S 84 36.0417 50 -0.07 95
GU.MGRO.HHZ. 2021-07-28T11:57:54.40 0.1 undecidable manual S 58 34.2435 50 0 97
GU.GBOS.HHZ. 2021-07-28T11:57:52.26 0.1 undecidable manual P 38 51.1155 50 0.27 89
GU.STV.HHZ. 2021-07-28T11:57:50.28 0.1 undecidable manual P 347 41.7249 50 -0.26 91
GU.MGRO.HHZ. 2021-07-28T11:57:49.54 0.1 positive manual P 58 34.2435 50 0.14 94
GU.IMI.HHZ. 2021-07-28T11:57:49.77 0.1 undecidable manual P 84 36.0417 50 0.09 95
GU.BURY.HHZ. 2021-07-28T11:57:48.42 0.3 undecidable manual S 140 13.9749 126 -0.14 73
FR.SAOF.HHZ.00 2021-07-28T11:57:48.73 0.1 undecidable manual S 36 14.6742 124 -0.04 100
FR.SAOF.HHZ.00 2021-07-28T11:57:46.24 0.1 positive manual P 36 14.6742 124 0.09 98
GU.BURY.HHZ. 2021-07-28T11:57:46.05 0.1 undecidable manual P 140 13.9749 126 0.02 100
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
GU.BURY.HHE. ML:0.8 0.00006185 0.44 AML other m 2021-07-28T11:57:48.47
FR.SAOF.HHE.00 ML:1.2 0.00014450000000000002 0.32 AML other m 2021-07-28T11:57:48.92
FR.SAOF.HHN.00 ML:1.4 0.0002155 1.72 AML other m 2021-07-28T11:57:49.12
GU.BURY.HHN. ML:0.8 0.00007065000000000001 0.64 AML other m 2021-07-28T11:57:49.34
GU.MGRO.HHE. ML:0.9 0.0000276 0.64 AML other m 2021-07-28T11:57:54.21
GU.IMI.HHE. ML:1.1 0.00004585 0.7 AML other m 2021-07-28T11:57:54.85
GU.IMI.HHN. ML:1.1 0.00005025 0.38 AML other m 2021-07-28T11:57:55.26
GU.MGRO.HHN. ML:1.1 0.000050749999999999994 0.46 AML other m 2021-07-28T11:57:55.75
GU.GBOS.HHE. ML:1.0 0.00002695 0.88 AML other m 2021-07-28T11:57:58.75
GU.GBOS.HHN. ML:0.9 0.0000193 0.48 AML other m 2021-07-28T11:58:00.34
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