ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA

Earthquake with magnitude of Mwp 6.4 on date 18-10-2017 and time 14:00:59 (Italy) in region Tonga Islands [Sea: Tonga]

A magnitude Mwp 6.4 earthquake occured in region: Tonga Islands [Sea: Tonga], on

  • 18-10-2017 12:00:59 (UTC)
  • 18-10-2017 14:00:59 (UTC +02:00) Italian time
  • 19-10-2017 01:00:59 (UTC +13:00) local time in the region of the earthquake (Pacific/Tongatapu)

and geographic coordinates (lat, lon) -20.47, -173.47 at 20 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

No Italian municipalities within 20 km distance.

Municipalities with at least 50000 inhabitants

No Italian municipalities within 100 km from the epicenter with at least 50000 inhabitants.

Recent and historical Seismicity
Seismic hazard
Shakemap
Felt maps
The earthquake effects in MCS scale as obtained from the compiled questionnaire

The earthquake effects in MCS scale as obtained from the compiled 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
Rev 100 mb 5.4
Mwp 6.4

Mwpd 6.5
2017-10-18
12:00:59
-20.47 -173.47 20 2017-10-18
12:21:36
Sala Sismica INGV-Roma 51094971
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2017-10-18 12:00:59
Latitude -20.47
Longitude -173.47
Depth (km) 20 (from location)
Evaluation mode of Origin automatic
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV-A
Event type earthquake
Origin ID 51094971

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 16501
Semi-minor axis of confidence ellipse (meter) 11322
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 327
Circular confidence region, given by single value of horizontal uncertainty (meter) 13334.1
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 84.2911
Number of associated phases, regardless of their use for origin computation 45
Number of defining phases 45
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 2.22654
Epicentral distance of station closest to the epicenter (degree) 3.60853
Epicentral distance of station farthest from the epicenter (degree) 74.54821
Number of stations at which the event was observed 43
Number of stations from which data was used for origin computation 43
Magnitudes information

Mwpd:6.5

Field Value
Value 6.5
Uncertainty 0.1
Num. used stations 23
Type of magnitude Mwpd
Reference to an origin 51094971
Agency INGV
Autore Auto added
Time of creation (UTC) 2017-10-18 12:21:36

Mwp:6.4

Field Value
Value 6.4
Uncertainty 0.1
Num. used stations 31
Type of magnitude Mwp
Reference to an origin 51094971
Agency INGV
Autore Auto added
Time of creation (UTC) 2017-10-18 12:21:36

mb:5.4

Field Value
Value 5.4
Uncertainty 0.1
Num. used stations 34
Type of magnitude mb
Reference to an origin 51094971
Agency INGV
Autore Auto added
Time of creation (UTC) 2017-10-18 12:21:36
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
GE.SMRI.BHZ. 2017-10-18T12:12:37.27 10.0 positive automatic P 268 74.5482 2.27626 0
IU.MAJO.BHZ.00 2017-10-18T12:12:26.02 10.0 positive automatic P 321 73.0088 0.0193899 0.220105
G.INU.BHZ.00 2017-10-18T12:12:26.26 10.0 positive automatic P 320 72.9054 0.918253 0
IU.QSPA.BHZ.00 2017-10-18T12:12:08.87 10.0 positive automatic P 180 69.4762 3.81681 0.273925
AU.MORW.BHZ. 2017-10-18T12:11:27.77 10.0 positive automatic P 247 63.6817 0.17117 0.352009
IU.NWAO.BHZ.00 2017-10-18T12:11:18.62 10.0 positive automatic P 243 62.0863 1.62738 0.308597
IU.MBWA.BHZ.00 2017-10-18T12:11:15.10 10.0 positive automatic P 256 61.9392 -0.879022 0.379583
GE.SANI.BHZ. 2017-10-18T12:11:13.82 10.0 positive automatic P 279 61.7754 -1.02697 0.360612
GE.SOEI.BHZ. 2017-10-18T12:11:08.62 10.0 positive automatic P 270 60.7279 0.690524 0.382802
IU.SBA.BHZ.00 2017-10-18T12:10:54.87 10.0 negative automatic P 185 58.1664 4.79788 0.427845
GE.BNDI.BHZ. 2017-10-18T12:10:42.42 10.0 positive automatic P 278 57.2263 -1.0281 0.387448
GE.FAKI.BHZ. 2017-10-18T12:10:31.12 10.0 positive automatic P 281 55.6652 -1.2317 0.38425
AU.WRKA.BHZ. 2017-10-18T12:10:15.30 10.0 positive automatic P 253 53.499 -1.41292 0.503655
AU.MTN.BHZ. 2017-10-18T12:10:13.75 10.0 positive automatic P 269 53.3856 -2.05098 0.457047
AU.FORT.BHZ. 2017-10-18T12:10:12.65 10.0 positive automatic P 246 53.1421 -1.36307 0.486399
AU.KDU.BHZ. 2017-10-18T12:10:05.32 10.0 positive automatic P 270 52.174 -1.5035 0.484799
II.WRAB.BHZ.00 2017-10-18T12:09:38.67 10.0 positive automatic P 261 48.7484 -2.31317 0.536973
AU.HTT.BHZ. 2017-10-18T12:09:01.95 10.0 positive automatic P 243 43.9654 -1.52321 0.689192
AU.COEN.BHZ. 2017-10-18T12:08:44.32 10.0 positive automatic P 272 41.8055 -1.56967 0.665359
II.TAU.BHZ.00 2017-10-18T12:08:28.92 10.0 negative automatic P 227 39.6686 0.693254 0.753699
IU.PMG.BHZ.00 2017-10-18T12:08:25.07 10.0 positive automatic P 280 39.4989 -1.73275 0.756989
AU.TOO.BHZ. 2017-10-18T12:08:24.80 10.0 positive automatic P 235 39.3507 -0.864692 0.759868
IU.CTAO.BHZ.00 2017-10-18T12:08:10.07 10.0 positive automatic P 263 37.686 -1.55782 0.811914
AU.MILA.BHZ. 2017-10-18T12:08:00.40 10.0 positive automatic P 235 36.4036 -0.405919 0.848561
G.CAN.BHZ.00 2017-10-18T12:07:56.75 10.0 positive automatic P 238 36.0664 -1.15581 0.78757
AU.ARMA.BHZ. 2017-10-18T12:07:30.27 10.0 positive automatic P 245 32.8991 -0.295997 0.74802
NZ.ODZ.HHZ.10 2017-10-18T12:06:49.77 10.0 positive automatic P 204 27.8558 3.91405 0.917431
NZ.KHZ.HHZ.10 2017-10-18T12:06:13.69 10.0 positive automatic P 204 24.52 -1.98492 0.328407
IU.SNZO.BHZ.00 2017-10-18T12:06:03.92 10.0 negative automatic P 203 23.1276 1.44953 0.769231
G.PPTF.BHZ.00 2017-10-18T12:06:03.25 10.0 negative automatic P 87 22.7551 4.61502 0.43956
ND.KOUNC.BHZ.00 2017-10-18T12:05:37.79 10.0 positive automatic P 266 20.8211 -0.0368333 0.888889
NZ.URZ.HHZ.10 2017-10-18T12:05:24.73 10.0 positive automatic P 203 19.5681 0.522064 0.921659
AU.NFK.BHZ. 2017-10-18T12:05:17.37 10.0 positive automatic P 239 18.9037 0.418435 0
ND.ONTNC.BHZ.00 2017-10-18T12:05:16.05 10.0 positive automatic P 261 18.7731 0.550775 0.43956
G.DZM.BHZ.00 2017-10-18T12:05:15.60 10.0 positive automatic P 261 18.7763 -0.0676793 0.909091
NZ.OUZ.HHZ.10 2017-10-18T12:05:12.17 10.0 positive automatic P 215 18.6297 -1.74571 0.328407
IU.RAO.BHZ.00 2017-10-18T12:04:58.22 10.0 negative automatic S 204 9.6631 -4.05398 0
ND.MARNC.BHZ.00 2017-10-18T12:04:57.59 10.0 positive automatic P 263 17.2968 -0.278463 0.547945
IU.FUNA.BHZ.00 2017-10-18T12:04:17.05 10.0 positive automatic P 328 13.8868 3.78196 0.97561
IU.RAR.BHZ.00 2017-10-18T12:03:57.27 10.0 negative automatic P 96 12.8135 -1.34009 0.615385
IU.RAO.BHZ.00 2017-10-18T12:03:14.05 10.0 negative automatic P 204 9.6631 -1.46791 0.869565
II.MSVF.BHZ.00 2017-10-18T12:03:03.57 10.0 positive automatic P 287 8.4624 4.39069 0.909091
IU.AFI.BHZ.00 2017-10-18T12:02:32.92 10.0 positive automatic P 14 6.7535 -2.7904 0.909091
AU.NIUE.BHZ. 2017-10-18T12:01:51.52 10.0 positive automatic P 68 3.6085 -0.869634 0.941176
TDMT - Time Domain Moment Tensor
Focal Mechanism in the area
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Type Description Link
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