Earthquake with magnitude of Mwp 6.4 on date 24-04-2021 and time 00:23:34 (UTC) in region Tonga [Sea]

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

  • 24-04-2021 00:23:34 (UTC)
  • 24-04-2021 02:23:34 (UTC +02:00) Italian time
  • 24-04-2021 13:23:34 (UTC +13:00) local time in the region of the earthquake (Pacific/Tongatapu)

and geographic coordinates (lat, lon) -18.759, -176.301 at 259 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

These three maps show the results of the analysis using the software ShakeMap designed to provide the level of ground shaking experienced in a region using the data recorded by seismometers and strong motion instruments and seismological information regarding the attenuation of the wavefield with distance and the site characteristics. The Shakemaps are determined for research purposes to provide fast estimates of the level of ground shaking produced by the earthquake. The maps are calculated automatically and adjourned progressively as more data become available. See http://shakemap.rm.ingv.it/ for additional information.

The red star indicates the epicenter. The red triangles show the stations of the INGV Italian National Seismic Network and the blue triangles those of the Nationa Accelerometric Network of the Dipartimento della Protezione Civile.

Intensity Shakemap

Intensity Shakemap

This map shows the distribution of the istrumentally derived intensities. To this purpose, it is used a conversion relation between ground acceleration and velocity, and the Mercalli Modificata (MMI - Modified Mercalli Intensity) scale. In general, the Mercalli intensity scale relies on the effects that the ground shaking produces as reported by an observer.
Peak ground acceleration Shakemap

Peak ground acceleration Shakemap

This map shows This map shows the distribution of peak ground acceleration expressed as per cent of the acceleration of gravity (i.e., g = 9.81 m/s²).
Peak velocity Shakemap

Peak velocity Shakemap

This map shows the distribution of peak ground velocities expressed in cm/s.
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
mb 5.6
Mwp 6.4

Mwpd 6.5
2021-04-24
00:23:34
-18.7594 -176.301 259 2021-04-24
00:38:59
Sala Sismica INGV-Roma 89420141
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-04-24 00:23:34
Latitude -18.7594
Longitude -176.3010
Depth (km) 259 (from location)
Evaluation mode of Origin automatic
Evaluation status of Origin reviewed
Version 100 -> SURVEY-INGV-A
Event type earthquake
Origin ID 89420141

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 11911
Semi-minor axis of confidence ellipse (meter) 4643
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 309
Circular confidence region, given by single value of horizontal uncertainty (meter) 10252.9
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 42.897
Number of associated phases, regardless of their use for origin computation 136
Number of defining phases 136
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 1.31201
Epicentral distance of station closest to the epicenter (degree) 6.50764
Epicentral distance of station farthest from the epicenter (degree) 88.00552
Number of stations at which the event was observed 112
Number of stations from which data was used for origin computation 112
Magnitudes information

Mwp:6.4

Field Value
Value 6.4
Uncertainty 0.2
Num. used stations 45
Type of magnitude Mwp
Reference to an origin 89420141
Agency INGV
Autore early-est_ee1.1.9
Time of creation (UTC) 2021-04-24 00:38:59

Mwpd:6.5

Field Value
Value 6.5
Uncertainty 0.2
Num. used stations 44
Type of magnitude Mwpd
Reference to an origin 89420141
Agency INGV
Autore early-est_ee1.1.9
Time of creation (UTC) 2021-04-24 00:38:59

mb:5.6

Field Value
Value 5.6
Uncertainty 0.1
Num. used stations 62
Type of magnitude mb
Reference to an origin 89420141
Agency INGV
Autore early-est_ee1.1.9
Time of creation (UTC) 2021-04-24 00:38:59
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
US.ISCO.BHZ.00 2021-04-24T00:35:54.53 10.0 positive automatic P 47 88.0055 -0.309336 0.109791
US.BOZ.BHZ.00 2021-04-24T00:35:48.93 10.0 positive automatic P 39 86.9191 -0.572769 0.113902
IU.PAYG.BHZ.00 2021-04-24T00:35:48.27 10.0 negative automatic PcP 89 86.006 1.14628 0
US.BW06.BHZ.00 2021-04-24T00:35:48.65 10.0 positive automatic P 42 86.7796 -0.288015 0
G.COYC.BHZ.00 2021-04-24T00:35:46.75 10.0 positive automatic P 137 86.163 1.13415 0.119596
US.MSO.BHZ.00 2021-04-24T00:35:44.93 10.0 positive automatic P 37 86.2125 -1.1093 0.122058
IU.COLA.BHZ.00 2021-04-24T00:35:43.20 10.0 positive automatic P 12 86.4199 -3.66253 0.123385
US.AHID.BHZ.00 2021-04-24T00:35:43.75 10.0 positive automatic P 42 85.7978 -0.381648 0.122397
IU.ANMO.BHZ.00 2021-04-24T00:35:41.20 10.0 negative automatic P 51 85.2216 -0.0788688 0.128374
G.UNM.BHZ.00 2021-04-24T00:35:40.75 10.0 positive automatic PcP 67 84.6786 -0.868857 0
US.MVCO.BHZ.00 2021-04-24T00:35:39.65 10.0 negative automatic P 48 84.8075 0.367649 0.130155
US.NEW.BHZ.00 2021-04-24T00:35:39.70 10.0 negative automatic P 35 85.2362 -1.4628 0.118499
US.HWUT.BHZ.00 2021-04-24T00:35:38.70 10.0 negative automatic P 43 84.9118 -1.04079 0
US.MNTX.BHZ.00 2021-04-24T00:35:38.55 10.0 negative automatic P 54 84.5805 0.702015 0.135109
US.HLID.BHZ.00 2021-04-24T00:35:35.53 10.0 negative automatic P 40 84.1601 -0.456584 0.130793
US.WRAK.BHZ.00 2021-04-24T00:35:33.05 10.0 positive automatic P 23 83.7324 -0.490561 0.142152
US.DUG.BHZ.00 2021-04-24T00:35:31.38 10.0 negative automatic P 43 83.3749 -0.596402 0
GE.BKNI.BHZ. 2021-04-24T00:35:31.12 10.0 negative automatic P 273 83.1535 0.520359 0
US.BMO.BHZ.00 2021-04-24T00:35:29.93 10.0 negative automatic P 38 83.1641 -0.916123 0.152415
AT.CRAG.BHZ. 2021-04-24T00:35:28.08 10.0 positive automatic P 23 82.7306 -0.359772 0.145172
US.HAWA.BHZ.00 2021-04-24T00:35:28.30 10.0 negative automatic P 36 82.8132 -0.614764 0.151795
IU.MA2.BHZ.00 2021-04-24T00:35:26.42 10.0 negative automatic P 344 82.8067 -2.45753 0
US.WUAZ.BHZ.00 2021-04-24T00:35:25.10 10.0 negative automatic P 48 81.9616 0.361782 0.155584
US.ELK.BHZ.00 2021-04-24T00:35:24.85 10.0 negative automatic P 42 82.11 -0.760435 0.149028
US.NLWA.BHZ.00 2021-04-24T00:35:19.68 10.0 negative automatic P 33 81.1295 -0.55789 0.162946
IU.TUC.BHZ.00 2021-04-24T00:35:19.17 10.0 negative automatic P 51 80.8029 0.610709 0.163954
US.WVOR.BHZ.00 2021-04-24T00:35:18.95 10.0 negative automatic P 39 80.9747 -0.592385 0.156949
RM.DLV.BHZ. 2021-04-24T00:35:16.97 10.0 negative automatic P 286 80.2227 1.42786 0.161656
GE.MNAI.BHZ. 2021-04-24T00:35:13.47 10.0 negative automatic P 269 79.8409 0.1453 0.145572
II.PFO.BHZ.00 2021-04-24T00:34:59.82 10.0 negative automatic P 48 77.3985 -0.419274 0.198057
ND.KOUNC.BHZ.00 2021-04-24T00:34:59.50 10.0 negative automatic ScP 261 18.3576 1.94825 0
NZ.OUZ.HHZ.10 2021-04-24T00:34:58.05 10.0 positive automatic ScP 206 18.7345 -0.325933 0
BK.CMB.BHZ.00 2021-04-24T00:34:58.10 10.0 positive automatic P 42 77.298 -1.48924 0.203845
ND.ONTNC.BHZ.00 2021-04-24T00:34:56.80 10.0 positive automatic ScP 255 16.5229 3.07692 0
BK.SAO.BHZ.00 2021-04-24T00:34:51.15 10.0 negative automatic P 42 75.8627 -0.358758 0.211021
BK.MCCM.BHZ.00 2021-04-24T00:34:50.77 10.0 negative automatic P 41 75.8064 -0.360962 0.0999828
IU.YSS.BHZ.00 2021-04-24T00:34:47.80 10.0 negative automatic P 332 75.3323 -0.676672 0.198007
IU.PET.BHZ.00 2021-04-24T00:34:44.22 10.0 negative automatic P 345 74.9827 -2.26063 0.215026
JP.JTU.BHZ. 2021-04-24T00:34:41.50 10.0 negative automatic P 316 74.1596 -0.260557 0.223425
MY.SBM.BHZ. 2021-04-24T00:34:38.37 10.0 positive automatic P 279 73.3397 1.32194 0.237346
JP.YOJ.BHZ. 2021-04-24T00:34:36.65 10.0 positive automatic P 304 73.2144 0.370732 0.233269
JP.JKA.BHZ. 2021-04-24T00:34:36.35 10.0 negative automatic PcP 328 70.9707 -5.41162 0
AT.AKUT.BHZ. 2021-04-24T00:34:35.62 10.0 negative automatic P 6 73.4505 -2.03401 0.244105
GE.SMRI.BHZ. 2021-04-24T00:34:30.27 10.0 negative automatic P 269 71.928 1.51487 0.258767
JP.JSU.BHZ. 2021-04-24T00:34:27.05 10.0 negative automatic P 314 71.6378 -0.0188428 0.2446
AT.SMY.BHZ. 2021-04-24T00:34:27.00 10.0 positive automatic P 354 71.9711 -1.9862 0.253452
II.ERM.BHZ.00 2021-04-24T00:34:25.72 10.0 negative automatic P 329 71.3726 0.29045 0.253059
JP.JTM.BHZ. 2021-04-24T00:34:25.35 10.0 positive automatic P 327 71.4958 -0.827624 0.246115
IU.QSPA.BHZ.00 2021-04-24T00:34:24.72 10.0 positive automatic P 180 71.1825 -0.0553705 0.273817
MY.KKM.BHZ. 2021-04-24T00:34:23.77 10.0 negative automatic P 284 70.9274 0.864205 0.270247
JP.JMN.BHZ. 2021-04-24T00:34:22.35 10.0 negative automatic P 318 70.761 0.491319 0.27218
AK.ATKA.BHZ. 2021-04-24T00:34:20.87 10.0 positive automatic P 1 70.9816 -2.22663 0.250531
IU.ADK.BHZ.00 2021-04-24T00:34:18.55 10.0 positive automatic P 360 70.6394 -2.51141 0.264163
JP.JGF.BHZ. 2021-04-24T00:34:15.30 10.0 positive automatic P 321 69.8623 -1.13746 0.269887
IU.MAJO.BHZ.00 2021-04-24T00:34:15.82 10.0 negative automatic P 322 70.0143 -1.50699 0.25651
G.INU.BHZ.00 2021-04-24T00:34:15.71 10.0 positive automatic P 321 69.8829 -0.773552 0.263662
MY.LDM.BHZ. 2021-04-24T00:34:10.57 10.0 negative automatic P 284 68.4964 2.56097 0.292216
JP.JSG.BHZ. 2021-04-24T00:34:09.95 10.0 positive automatic P 321 68.7337 0.492613 0.282817
GE.JAGI.BHZ. 2021-04-24T00:34:04.07 10.0 negative automatic P 268 67.9951 -0.839029 0.29822
JP.JHJ2.BHZ. 2021-04-24T00:33:56.85 10.0 positive automatic P 321 66.675 0.20797 0.307182
IU.CASY.BHZ.00 2021-04-24T00:33:52.82 10.0 negative automatic P 205 66.1215 -0.315104 0.300255
AU.GIRL.BHZ.00 2021-04-24T00:33:43.80 10.0 positive automatic P 253 64.5072 0.967733 0.354041
II.KAPI.BHZ.00 2021-04-24T00:33:38.42 10.0 negative automatic P 274 63.7412 0.51878 0.360006
GE.LUWI.BHZ. 2021-04-24T00:33:29.52 10.0 negative automatic P 279 62.2304 1.57834 0.190256
II.RPN.BHZ.00 2021-04-24T00:33:24.92 10.0 positive automatic P 111 61.5491 1.482 0.372219
AU.MORW.BHZ. 2021-04-24T00:33:24.85 10.0 positive automatic P 246 61.9085 -1.0151 0.355342
JP.JCJ.BHZ. 2021-04-24T00:33:19.15 10.0 negative automatic P 318 61.0035 -0.651405 0.333968
IU.NWAO.BHZ.00 2021-04-24T00:33:16.22 10.0 negative automatic P 242 60.5098 -0.309568 0.395147
IU.SBA.BHZ.00 2021-04-24T00:33:12.12 10.0 positive automatic P 184 59.6631 1.37372 0.203484
GT.VNDA.BHZ.00 2021-04-24T00:33:11.78 10.0 positive automatic P 185 59.7352 0.526677 0.420628
IU.MBWA.BHZ.00 2021-04-24T00:33:10.92 10.0 positive automatic P 256 59.7571 -0.489144 0.42031
GE.SANI.BHZ. 2021-04-24T00:33:05.87 10.0 negative automatic P 279 58.8667 0.561642 0.428204
GE.SOEI.BHZ. 2021-04-24T00:33:02.02 10.0 negative automatic P 270 58.0544 2.1233 0.440143
GE.BNDI.BHZ. 2021-04-24T00:32:34.47 10.0 negative automatic P 278 54.3414 0.8988 0.434708
GE.FAKI.BHZ. 2021-04-24T00:32:22.47 10.0 negative automatic P 281 52.7183 0.621083 0.4989
AU.WRKA.BHZ.00 2021-04-24T00:32:12.43 10.0 positive automatic P 252 51.4461 -0.173405 0.556628
AU.FORT.BHZ.00 2021-04-24T00:32:11.55 10.0 positive automatic P 245 51.4105 -0.70659 0.557227
AU.MTN.BHZ.00 2021-04-24T00:32:07.53 10.0 negative automatic P 269 50.7527 0.147105 0.523668
IU.GUMO.BHZ.00 2021-04-24T00:32:02.97 10.0 negative automatic P 307 50.1009 0.444945 0.552564
AU.KDU.BHZ.00 2021-04-24T00:31:58.43 10.0 positive automatic P 269 49.5218 0.264364 0.582412
IU.MIDW.BHZ.00 2021-04-24T00:31:38.22 10.0 negative automatic P 359 46.9843 -0.629861 0.597868
II.WRAB.BHZ.00 2021-04-24T00:31:34.02 10.0 positive automatic P 260 46.3959 -0.347375 0.65291
GE.GENI.BHZ. 2021-04-24T00:31:28.87 10.0 positive automatic P 285 45.5445 1.17558 0.552644
G.KIP.BHZ.00 2021-04-24T00:31:15.35 10.0 positive automatic P 25 43.9851 -0.105932 0.681095
IU.POHA.BHZ.00 2021-04-24T00:31:11.90 10.0 positive automatic P 29 43.569 -0.581827 0.642386
AU.HTT.BHZ. 2021-04-24T00:31:02.62 10.0 positive automatic P 241 42.4273 -0.527044 0.685475
IU.WAKE.BHZ.00 2021-04-24T00:30:55.72 10.0 negative automatic P 335 41.5563 -0.297918 0.718167
AU.MCQ.BHZ.00 2021-04-24T00:30:47.05 10.0 positive automatic P 202 40.4279 0.196631 0.767051
II.TAU.BHZ.00 2021-04-24T00:30:34.62 10.0 positive automatic P 224 38.9827 -0.393474 0.732751
AU.QLP.BHZ. 2021-04-24T00:30:19.52 10.0 positive automatic P 250 37.0926 0.217389 0.824664
GE.PMG.BHZ.00 2021-04-24T00:30:16.17 10.0 negative automatic P 280 36.576 1.22711 0.744498
G.TAOE.BHZ.00 2021-04-24T00:30:15.10 10.0 positive automatic P 79 36.3939 1.56797 0.811347
IU.JOHN.BHZ.00 2021-04-24T00:30:10.90 10.0 positive automatic P 11 36.1103 -0.109635 0.796368
AU.MILA.BHZ.00 2021-04-24T00:30:04.33 10.0 positive automatic P 232 35.2902 0.129656 0.736317
IU.CTAO.BHZ.00 2021-04-24T00:30:04.05 10.0 positive automatic P 261 35.2635 0.148824 0.813016
G.CAN.BHZ.00 2021-04-24T00:30:00.35 10.0 positive automatic P 234 34.8042 0.308778 0.794716
AU.RIV.BHZ. 2021-04-24T00:29:42.37 10.0 positive automatic P 236 32.6335 1.08934 0.836968
II.KWJN.BHZ.00 2021-04-24T00:29:39.12 10.0 negative automatic P 329 32.2588 1.09031 0.863561
AU.ARMA.BHZ. 2021-04-24T00:29:30.17 10.0 positive automatic P 242 31.2648 0.601878 0.937052
AU.EIDS.BHZ. 2021-04-24T00:29:26.20 10.0 positive automatic P 252 30.8588 0.329925 0.882122
NZ.ODZ.HHZ.10 2021-04-24T00:29:02.40 10.0 positive automatic P 200 28.4389 -2.18471 0.985222
IU.XMAS.BHZ.00 2021-04-24T00:28:59.45 10.0 positive automatic P 44 27.8675 -0.0418472 0.941176
AU.LHI.BHZ.00 2021-04-24T00:28:40.68 10.0 positive automatic P 235 25.6009 1.34225 0.43956
G.PPTF.BHZ.00 2021-04-24T00:28:38.35 10.0 positive automatic P 92 25.4043 0.668799 0.952381
IU.HNR.BHZ.00 2021-04-24T00:28:32.42 10.0 negative automatic P 289 24.8118 0.174202 0.833333
NZ.KHZ.HHZ.10 2021-04-24T00:28:32.70 10.0 positive automatic P 198 25.175 -2.80849 0.97561
IU.SNZO.BHZ.00 2021-04-24T00:28:20.42 10.0 positive automatic P 197 23.8212 -2.8809 0.963855
IU.TARA.BHZ.00 2021-04-24T00:28:12.92 10.0 negative automatic P 331 22.7321 -0.475011 0.808081
IU.RAO.BHZ.00 2021-04-24T00:27:52.55 10.0 positive automatic S 188 10.5896 -4.59049 0
NZ.OUZ.HHZ.10 2021-04-24T00:27:33.09 10.0 positive automatic P 206 18.7345 -0.354494 0.961538
IU.RAR.BHZ.00 2021-04-24T00:27:03.12 10.0 positive automatic P 102 15.7162 2.452 0.97561
IU.FUNA.BHZ.00 2021-04-24T00:26:09.77 10.0 negative automatic P 336 11.1264 3.72627 0.91954
IU.RAO.BHZ.00 2021-04-24T00:25:59.12 10.0 positive automatic P 188 10.5896 -0.239068 0.941176
IU.AFI.BHZ.00 2021-04-24T00:25:06.82 10.0 positive automatic P 42 6.5076 -1.44554 0.91954
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