Earthquake with magnitude of ML 2.3 on date 17-02-2021 and time 21:18:30 (Italy) in region 3 km SW Castelbianco (SV)

A magnitude ML 2.3 earthquake occured in region: 3 km SW Castelbianco (SV), on

  • 17-02-2021 20:18:30 (UTC)
  • 17-02-2021 21:18:30 (UTC +01:00) Italian time

and geographic coordinates (lat, lon) 44.1, 8.06 at 10 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.

Municipalities within 20 km from the epicenter

Distances are determinated based on the geographic coordintes of the (Istat).
Municipality Region Dist Inh Cum Inh
Castelbianco SV 3 330 330
Vendone SV 3 388 718
Onzo SV 3 219 937
Nasino SV 3 207 1144
Aquila d'Arroscia IM 4 166 1310
Arnasco SV 4 645 1955
Alto CN 5 128 2083
Zuccarello SV 5 309 2392
Ranzo IM 5 557 2949
Ortovero SV 5 1586 4535
Castelvecchio di Rocca Barbena SV 6 145 4680
Erli SV 6 245 4925
Casanova Lerrone SV 7 749 5674
Cisano sul Neva SV 7 2085 7759
Borghetto d'Arroscia IM 7 456 8215
Garlenda SV 8 1254 9469
Caprauna CN 9 104 9573
Villanova d'Albenga SV 9 2657 12230
Vessalico IM 9 282 12512
Balestrino SV 10 595 13107
Testico SV 10 196 13303
Stellanello SV 11 808 14111
Armo IM 12 111 14222
Garessio CN 12 3244 17466
Cesio IM 12 283 17749
Bardineto SV 12 756 18505
Pieve di Teco IM 13 1338 19843
Toirano SV 13 2644 22487
Ormea CN 13 1617 24104
Alassio SV 13 10934 35038
Albenga SV 13 24213 59251
Caravonica IM 14 282 59533
Boissano SV 14 2492 62025
Ceriale SV 14 5561 67586
Villa Faraldi IM 14 444 68030
Chiusanico IM 15 607 68637
Borghetto Santo Spirito SV 15 4948 73585
Pornassio IM 15 685 74270
Chiusavecchia IM 15 577 74847
Laigueglia SV 16 1810 76657
Lucinasco IM 16 272 76929
Borgomaro IM 16 865 77794
Diano Arentino IM 16 722 78516
Calizzano SV 16 1475 79991
Aurigo IM 16 347 80338
Andora SV 17 7552 87890
Loano SV 17 11407 99297
Rezzo IM 17 366 99663
Priola CN 17 701 100364
Giustenice SV 17 977 101341
Pontedassio IM 18 2323 103664
Cosio d'Arroscia IM 18 221 103885
Diano San Pietro IM 18 1145 105030
San Bartolomeo al Mare IM 19 3129 108159
Magliolo SV 19 974 109133
Pietra Ligure SV 19 8992 118125
Diano Castello IM 19 2214 120339
Tovo San Giacomo SV 19 2582 122921
Cervo IM 19 1187 124108
Montegrosso Pian Latte IM 19 118 124226
Vasia IM 20 389 124615

Municipalities with at least 50000 inhabitants

An earthquake occurred to
37 Km NE of Sanremo (54807 inhabitants)
41 Km SW of Savona (61345 inhabitants)
52 Km SE of Cuneo (56081 inhabitants)
78 Km W of Genova (586655 inhabitants)
90 Km S of Asti (76202 inhabitants)
Recent and historical seismicity

These maps show the seismicity for different time windows. The earthquake locations reported in these maps are determined in quasi real-time by the personnel on duty in the seismic surveillance center of INGV in Rome. Note that the earthquake source parameters (hypocentral location and magnitude) are the best estimates obstained with the available data and they are adjourned as additional data become available. The source parameters obtained by the personnel on duty are then revised by the group in charge of the INGV Seismic Bulletin (Bollettino Sismico Italiano dell’INGV).

Earthquakes of the 3 days preceding this event

Earthquakes of the 3 days preceding this event

This map reports the earthquake epicenters located in the 72 hours (3 days) preceding the time of the current earthquake occurrence, using the data acquired by the Italian National Seismic Network and by other collaborating networks in Italy and in the neighbouring countries. The radius of the circle representing the earthquake on the map scales with magnitude. The color depends on the time of occurrence of the earthquakes with respect to the time of generation of the map (red = 1 hour; orange = 24 hours; yellow = 72 hours). The open star shows the epicenter of the current earthquake.
Earthquakes of the 90 days preceding this event

Earthquakes of the 90 days preceding this event

This map reports the Magnitudo ≥ 1.0 earthquake epicenters located in the 90 days preceding the time of the current earthquake occurrence, using the data acquired by the Italian National Seismic Network and by other collaborating networks in Italy and in the neighbouring countries. The radii of the circles representing the epicenters on the map scale with magnitude. The color of each circle depends on the time of occurrence of the earthquakes with respect to the time of generation of the map (red = 1 hour; orange = 24 hours; yellow = 72 hours; blue = all other earthquakes). The open star shows the epicenter of the current earthquake.
Earthquakes from 1985 to the date of the event

Earthquakes from 1985 to the date of the event

This map reports the Magnitudo ≥ 2.5 earthquake epicenters located using the data acquired by the Italian National Seismic Network and by other collaborating networks in Italy and in the neighbouring countries. The radii of the circles representing the epicenters on the map scale with magnitude. The color of each circle depends on the time of occurrence of the earthquakes with respect to the time of generation of the map (red = 1 hour; orange = 24 hours; yellow = 72 hours; blue = all other earthquakes). The open star shows the epicenter of the current earthquake.
Earthquakes since 1000 AD until 2019

Earthquakes since 1000 AD until 2019

This map shows the epicenters of the historical earthquakes catalogue CPT15 (Catalogo Parametrico dei Terremoti Italiani, 2015 version https://emidius.mi.ingv.it/CPTI15-DBMI15/) with estimated magnitude ≥ 5.0 since 1000 AD until 2014. The epicenters are represented by squares which sides scale with the estimated earthquake magnitude. For earthquakes with magnitude ≥ 6.0, it is also shown the year of occurrence and the magnitude value. The open star shows the epicenter of the current earthquake.
Seismic hazard

Seismic hazard maps provide probabilistic estimates of the earthquake ground shaking exceeding a given threshold in a given geographic region within a given time window. Thus, it is not a deterministic prediction - a target that may be never reached given the complexity of the earthquake physical phenomenon - nor of the maximum expected earthquake since this has extremely low probabilities to occur.

In 2004, it was published the seismic hazard map of Italy (http://zonesismiche.mi.ingv.it) that provides a picture of the most hazardous geographic regions. The seismic hazard map of Italy (GdL MPS, 2004; rif. Ordinanza PCM del 28 aprile 2006, n. 3519, All. 1b) provides the 10% probability of exceedance in 50 years of the horizontal acceleration at rock sites (i.e., Vs30>800 m/s; cat. A, 3.2.1 of the D.M. 14.09.2005).

The colours indicate the various values of the ground acceleration that have 10% to be exceeded within 50 years. In general, the colours associated to low values of acceleration refer to areas that are less hazardous and stronger earthquakes repeat less frequently although they may still occur.

Seismic hazard map

Seismic hazard map

This map shows the seismic hazard map of Italy for the region where the earthquake occurred.
Shakemap
Felt maps
Preliminary map of the earthquake effects from the web questionnaire

Preliminary map of the earthquake effects from the web questionnaire

This map shows the distribution of the effects of the earthquake on the territory in terms of the MCS (Mercalli-Cancani-Sieberg) intensity scale. The intensities are determined using the data provided in the questionnaire (http://www.haisentitoilterremoto.it/) that are analysed using robust statistical techniques since they are not verified individually. Specifically, the assignment of MCS intensities greater or equal the VI degree of the MCS scale require opportune in situ verification by professional experts. The purple start shows the epicenter. This map is prepared every so often that the population fill in new questionnaires. The number of questionnaires used to determine the map and the date and time of the last adjournment are shown in the upper right part of the panel.
Locations history
Type Magnitude Date and Time (UTC) Latitude Longitude Depth (km) Published time (UTC) Author Location ID
Reviewed
Rev100
Md 1.7
ML 2.3
2021-02-17
20:18:30
44.1 8.06 10 2021-02-17
20:53:22
Sala Sismica INGV-Roma 87253901
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-02-17 20:18:30 ± 0.31
Latitude 44.10 ± 0.02
Longitude 8.06 ± 0.01
Depth (km) 10 ± 1 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV
Event type earthquake
Origin ID 87253901

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 2067
Semi-minor axis of confidence ellipse (meter) 654
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 348
Circular confidence region, given by single value of horizontal uncertainty (meter) 2070
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 204
Number of associated phases, regardless of their use for origin computation 25
Number of defining phases 10
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.39
Epicentral distance of station closest to the epicenter (degree) 0
Epicentral distance of station farthest from the epicenter (degree) 0.9317
Number of stations at which the event was observed 18
Number of stations from which data was used for origin computation 5
Magnitudes information

ML:2.3

Field Value
Value 2.3
Uncertainty 0
Num. used stations 2
Type of magnitude ML
Reference to an origin 87253901
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-02-17 20:53:22

Md:1.7

Field Value
Value 1.7
Uncertainty 0.2
Num. used stations 3
Type of magnitude Md
Reference to an origin 87253901
Agency INGV
Autore Sala Sismica INGV-Roma
Time of creation (UTC) 2021-02-17 20:53:22
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
ST.PANI.EHZ. 2021-02-17T20:19:19.98 3.0 undecidable manual Sg 17.26 0
GU.BLANC.HHZ. 2021-02-17T20:19:08.35 3.0 positive manual Pg 17.059999 0
IV.MONC.HHZ. 2021-02-17T20:19:05.47 3.0 undecidable manual S 0
RD.ORIF.BHZ. 2021-02-17T20:19:04.92 3.0 negative manual Pn 8.57 0
GU.BHB.HHZ. 2021-02-17T20:19:00.80 0.6 undecidable manual S 323 0.9317 50 0.2 43
IV.MTGR.HHZ. 2021-02-17T20:18:52.79 3.0 positive manual Pg 11.08 0
IV.MONC.HHZ. 2021-02-17T20:18:50.82 3.0 negative manual Pg 12.71 0
GU.BHB.HHZ. 2021-02-17T20:18:48.44 0.3 negative manual P 323 0.9317 50 0.65 57
IV.FREG.EHZ. 2021-02-17T20:18:48.26 3.0 undecidable manual Sn -5.6 0
FR.SAOF.HHZ.00 2021-02-17T20:18:43.70 0.3 undecidable manual S 253 0.3786 50 -0.51 67
IV.QLNO.HHZ. 2021-02-17T20:18:41.50 0.6 undecidable manual S 42 0.3076 50 -0.6 44
FR.SAOF.HHZ.00 2021-02-17T20:18:38.48 0.6 positive manual P 253 0.3786 50 0.15 48
GU.GBOS.HHZ. 2021-02-17T20:18:38.70 0.6 undecidable manual S 313 0.214 113 -0.53 46
IV.QLNO.HHZ. 2021-02-17T20:18:37.28 0.1 positive manual P 42 0.3076 50 0.17 98
GU.CANO.HHZ. 2021-02-17T20:18:37.20 0.6 undecidable manual S 49 0.17 118 -0.51 47
GU.GBOS.HHZ. 2021-02-17T20:18:35.66 0.1 negative manual P 313 0.214 113 0.2 99
GU.CANO.HHZ. 2021-02-17T20:18:34.77 0.1 undecidable manual P 49 0.17 118 0.2 100
ST.CARE.EHZ. 2021-02-17T20:18:31.32 3.0 negative manual Pn 2.93 0
IV.PESA.HHZ. 2021-02-17T20:18:05.32 3.0 undecidable manual Sn -0.64 0
IV.IMOL.HNZ. 2021-02-17T20:18:00.95 3.0 negative manual Pn 0.24 0
IV.ASSB.HHZ. 2021-02-17T20:17:59.54 3.0 undecidable manual Sg 0.15 0
IV.SRES.HHZ. 2021-02-17T20:17:49.23 3.0 undecidable manual P -0.4 0
IV.ASSB.HHZ. 2021-02-17T20:17:44.97 3.0 undecidable manual P -0.12 0
IV.RM33.HNZ. 2021-02-17T20:17:41.32 3.0 undecidable manual P -0.29 0
IV.MF5.EHZ. 2021-02-17T20:17:37.90 3.0 negative manual P 0.89 0
Station Magnitude and Amplitude
SCNL mag Generic_amplitude Period Type Category Unit Time_window_reference
GU.GBOS.HHE. ML:2.3 0.001245 0.9 AML other m 2021-02-17T20:18:39.54
IV.IMI.HHN. ML:0 0.00226 1.58 AML other m 2021-02-17T20:18:39.14
IV.IMI.HHE. ML:0 0.00166 0.8 AML other m 2021-02-17T20:18:39.10
GU.GBOS.HHN. ML:2.3 0.00125 0.32 AML other m 2021-02-17T20:18:39.81
GU.CANO.HHZ. Md:1.6 15 END duration s
GU.GBOS.HHZ. Md:1.7 17 END duration s
IV.QLNO.HHZ. Md:1.9 22 END duration s
TDMT - Time Domain Moment Tensor
Fault Plane solutions in the area
Fault Plane solutions

Fault Plane solutions

This map reports the focal mechanisms since 1977 in the region. The white and red beach ball symbols are mechanisms determined using the Regional Centroid Moment Tensor (RCMT, http://www.bo.ingv.it/RCMT) and are determined for earthquakes with magnitude larger than 4.5 in the Euro-Mediterranenan area. Occasionally, when there is a good source-receiver geometry of the target earthquake, the RCMT can be obtained also for earthquakes with magnitude larger than 4.0. The blue and white beach ball symbols indicate the mechanisms obtained from application of the Time Domain Moment Tensor (TDMT, http://terremoti.ingv.it/tdmt.html). This technique is used for M ≥ 3.5. The size of the beach ball sysmbol scales with the calculated moment magnitude, Mw.
Download
Type Description Link
QuakeML - small Event, Origin, FocalMechanism Download
QuakeML - full Event, Origin, FocalMechanism, Amplitude, Arrival, Pick, Station Magnitude Download
Waveforms Seismic signals in miniseed + resp format Download