Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of Md 2.5 on date 18-08-1986 and time 11:30:22 (Italy) in region S Triora (IM)

A magnitude Md 2.5 earthquake occured in region: S Triora (IM), on

  • 18-08-1986 09:30:22 (UTC)
  • 18-08-1986 11:30:22 (UTC +02:00) Italian time

and geographic coordinates (lat, lon) 43.9940, 7.7630 at 4 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
Triora IM 0 355 355
Molini di Triora IM 1 617 972
Carpasio IM 9 168 1140
Rezzo IM 9 366 1506
Montegrosso Pian Latte IM 9 118 1624
Montalto Ligure IM 10 377 2001
Mendatica IM 10 185 2186
Briga Alta CN 10 39 2225
Castel Vittorio IM 10 287 2512
Pigna IM 10 859 3371
Bajardo IM 11 312 3683
Cosio d'Arroscia IM 11 221 3904
Badalucco IM 11 1136 5040
Pornassio IM 12 685 5725
Ceriana IM 13 1250 6975
Aurigo IM 13 347 7322
Pieve di Teco IM 14 1338 8660
Borgomaro IM 15 865 9525
Apricale IM 15 629 10154
Perinaldo IM 16 870 11024
Caravonica IM 16 282 11306
Prelà IM 16 503 11809
Isolabona IM 16 679 12488
Armo IM 16 111 12599
Pietrabruna IM 16 501 13100
Lucinasco IM 16 272 13372
Castellaro IM 17 1256 14628
Vasia IM 17 389 15017
Vessalico IM 17 282 15299
Cesio IM 17 283 15582
Rocchetta Nervina IM 17 298 15880
Chiusavecchia IM 18 577 16457
Dolcedo IM 18 1415 17872
Taggia IM 18 14116 31988
Chiusanico IM 19 607 32595
Pompeiana IM 19 823 33418
Terzorio IM 19 216 33634
Borghetto d'Arroscia IM 19 456 34090
Sanremo IM 19 54807 88897
Seborga IM 19 315 89212
Dolceacqua IM 20 2074 91286
Civezza IM 20 609 91895
Riva Ligure IM 20 2910 94805

Municipalities with at least 50000 inhabitants

An earthquake occurred to
19 Km N of Sanremo (54807 inhabitants)
48 Km SE of Cuneo (56081 inhabitants)
67 Km SW 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 		Md 2.5
M 3.1 		1986-08-18
09:30:22		 43.994 7.763 4 2013-07-15
08:40:51		 Bollettino Sismico Italiano INGV 32939
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 1986-08-18 09:30:22 ± 0.19
Latitude 43.9940 ± 0.0140
Longitude 7.7630 ± 0.0117
Depth (km) 4 ± 2 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> BULLETIN-VAX
Event type earthquake
Origin ID 32939

Uncertainty

Field Value
Preferred uncertainty description horizontal uncertainty
Semi-major axis of confidence ellipse (meter)
Semi-minor axis of confidence ellipse (meter)
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi)
Circular confidence region, given by single value of horizontal uncertainty (meter) 1813.8
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 180
Number of associated phases, regardless of their use for origin computation 14
Number of defining phases 14
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.3
Epicentral distance of station closest to the epicenter (degree) 0.00105
Epicentral distance of station farthest from the epicenter (degree) 0.01036
Number of stations at which the event was observed 8
Number of stations from which data was used for origin computation 8
Magnitudes information

Md:2.5

Field Value
Value 2.5
Uncertainty
Num. used stations 2
Type of magnitude Md
Reference to an origin 32939
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2013-01-04 17:33:42

M:3.1

Field Value
Value 3.1
Uncertainty
Num. used stations
Type of magnitude M
Reference to an origin 32939
Agency INGV
Autore Bollettino Sismico Italiano INGV
Time of creation (UTC) 2015-04-28 09:48:29
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
--.RRL.Z. 1986-08-18T09:31:03.40 10.0 undecidable manual SN 323 1.1544 0.9 0.1
--.SOO.Z. 1986-08-18T09:30:47.70 10.0 undecidable manual SG 317 0.6882 -0.52 0.3
--.DA9.Z. 1986-08-18T09:30:45.50 10.0 undecidable manual SG 324 0.6327 -0.58 0.3
--.RRL.Z. 1986-08-18T09:30:45.80 10.0 undecidable manual PN 323 1.1544 0.09 1
--.CKI.Z. 1986-08-18T09:30:43.50 10.0 undecidable manual SG 40 0.555 -0.45 0.4
--.STV.Z. 1986-08-18T09:30:38.00 10.0 undecidable manual SG 309 0.3996 -0.37 0.7
--.FIN.Z. 1986-08-18T09:30:37.50 10.0 undecidable manual SG 56 0.3774 -0.16 0.6
--.SOO.Z. 1986-08-18T09:30:37.60 10.0 undecidable manual PG 317 0.6882 0.13 1.3
--.DA9.Z. 1986-08-18T09:30:36.50 10.0 undecidable manual PG 324 0.6327 0.27 1.2
--.CKI.Z. 1986-08-18T09:30:35.20 10.0 undecidable manual PG 40 0.555 0.2 1.4
--.ROB.Z. 1986-08-18T09:30:31.00 10.0 undecidable manual PG 14 0.3108 1.11 0.3
--.FIN.Z. 1986-08-18T09:30:31.30 10.0 undecidable manual PG 56 0.3774 -0.07 1.4
--.STV.Z. 1986-08-18T09:30:31.90 10.0 undecidable manual PG 309 0.3996 0.12 2.9
--.IMP.Z. 1986-08-18T09:30:25.20 10.0 undecidable manual PG 129 0.1221 -0.39 2.2
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