Earthquake with magnitude of Mwp 6.0 on date 25-09-2021 and time 05:21:36 (UTC) in region South of Africa [Sea]

A magnitude Mwp 6.0 earthquake occured in region: South of Africa [Sea], on

  • 25-09-2021 05:21:36 (UTC)
  • 25-09-2021 07:21:36 (UTC +02:00) Italian time
  • 25-09-2021 08:21:36 (UTC +03:00) local time in the region of the earthquake (Antarctica/Syowa)

and geographic coordinates (lat, lon) -53.304, 23.566 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

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 5.2
Mwp 6.0

Mwpd 6.1
2021-09-25
05:21:36
-53.3039 23.5657 20 2021-09-25
05:44:57
Sala Sismica INGV-Roma 95856241
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2021-09-25 05:21:36
Latitude -53.3039
Longitude 23.5657
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 95856241

Uncertainty

Field Value
Preferred uncertainty description uncertainty ellipse
Semi-major axis of confidence ellipse (meter) 14854
Semi-minor axis of confidence ellipse (meter) 659
Azimuth of major axis of confidence ellipse. Measured clockwise from South-North direction at epicenter (gradi) 88
Circular confidence region, given by single value of horizontal uncertainty (meter) 11992.6
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree) 63.3852
Number of associated phases, regardless of their use for origin computation 43
Number of defining phases 43
RMS of the travel time residuals of the arrivals used for the origin computation (sec) 0.909776
Epicentral distance of station closest to the epicenter (degree) 20.12671
Epicentral distance of station farthest from the epicenter (degree) 93.60298
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:6.1

Field Value
Value 6.1
Uncertainty 0.1
Num. used stations 13
Type of magnitude Mwpd
Reference to an origin 95856241
Agency INGV
Autore early-est_ee1.1.9
Time of creation (UTC) 2021-09-25 05:44:57

Mwp:6

Field Value
Value 6
Uncertainty 0.1
Num. used stations 12
Type of magnitude Mwp
Reference to an origin 95856241
Agency INGV
Autore early-est_ee1.1.9
Time of creation (UTC) 2021-09-25 05:44:57

mb:5.2

Field Value
Value 5.2
Uncertainty 0.1
Num. used stations 34
Type of magnitude mb
Reference to an origin 95856241
Agency INGV
Autore early-est_ee1.1.9
Time of creation (UTC) 2021-09-25 05:44:57
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance Takeoff_angle Residual Weight
IU.ANTO.BHZ.00 2021-09-25T05:38:34.07 10.0 negative automatic PP 7 93.5085 0.189904 0
MN.VSL.BHZ. 2021-09-25T05:38:33.42 10.0 negative automatic PP 349 93.603 -1.07451 0
HL.KEK.HHZ. 2021-09-25T05:38:27.04 10.0 negative automatic PP 357 93.0696 -3.25479 0
GE.APE.BHZ. 2021-09-25T05:38:07.90 10.0 negative automatic PP 2 90.3849 -1.26775 0
HL.ARG.HHZ. 2021-09-25T05:38:04.69 10.0 positive automatic PP 4 89.6008 1.84413 0
MN.TIP.BHZ. 2021-09-25T05:34:44.37 10.0 negative automatic P 355 92.6665 -1.10386 0.0700755
HT.AGG.HHZ. 2021-09-25T05:34:42.53 10.0 positive automatic P 359 92.327 -1.35236 0.0796198
IU.CTAO.BHZ.00 2021-09-25T05:34:39.17 10.0 positive automatic P 128 91.5835 -1.22542 0.0845957
AU.KDU.BHZ.00 2021-09-25T05:34:35.98 10.0 positive automatic P 113 90.7299 -0.404263 0.0891844
AU.MTN.BHZ.00 2021-09-25T05:34:31.98 10.0 positive automatic P 112 89.8591 -0.360975 0.0950792
GE.SOEI.BHZ. 2021-09-25T05:34:26.97 10.0 negative automatic P 104 88.4776 0.963903 0.0978318
NZ.OUZ.HHZ.10 2021-09-25T05:34:23.32 10.0 positive automatic P 156 87.73 1.02702 0.105756
II.WRAB.BHZ.00 2021-09-25T05:34:12.60 10.0 positive automatic P 118 85.7566 -0.112988 0.130036
AU.QLP.BHZ. 2021-09-25T05:34:09.55 10.0 negative automatic P 129 85.0495 0.389929 0.123678
GE.MSBI.BHZ. 2021-09-25T05:34:09.25 10.0 positive automatic P 10 85.2325 -0.746624 0.123677
II.UOSS.BHZ.00 2021-09-25T05:33:57.02 10.0 negative automatic P 30 83.2141 -2.80484 0.136528
II.RAYN.BHZ.00 2021-09-25T05:33:37.35 10.0 negative automatic P 20 79.1471 -0.925294 0.185242
AU.WRKA.BHZ.00 2021-09-25T05:33:33.45 10.0 positive automatic P 117 78.3618 -0.499405 0.155446
GT.LPAZ.BHZ.00 2021-09-25T05:33:32.48 10.0 negative automatic P 259 77.9972 -0.172662 0.191891
AU.HTT.BHZ. 2021-09-25T05:33:26.10 10.0 positive automatic P 129 76.8069 0.812228 0.198946
IU.MBWA.BHZ.00 2021-09-25T05:33:24.32 10.0 positive automatic P 108 76.725 -0.408189 0.19309
IU.LCO.BHZ.00 2021-09-25T05:32:42.57 10.0 positive automatic P 249 69.5104 0.130731 0.26164
AU.MORW.BHZ. 2021-09-25T05:32:35.67 10.0 positive automatic P 110 68.4658 0.06201 0.299168
G.ATD.BHZ.00 2021-09-25T05:32:26.25 10.0 negative automatic P 21 66.8937 0.511983 0.304173
IU.NWAO.BHZ.00 2021-09-25T05:32:21.27 10.0 positive automatic P 114 66.1864 0.0895426 0.320008
GT.DBIC.BHZ.00 2021-09-25T05:32:08.40 10.0 negative automatic P 328 64.6026 -2.48082 0.332336
GT.CPUP.BHZ.00 2021-09-25T05:32:05.48 10.0 positive automatic P 260 63.8689 -0.594877 0.326765
BL.PMNB.HHZ. 2021-09-25T05:32:02.66 10.0 positive automatic P 274 63.3387 -0.0512632 0.361552
C.GO06.BHZ. 2021-09-25T05:31:53.70 10.0 positive automatic P 240 61.9317 0.321008 0.384205
GT.PLCA.BHZ.00 2021-09-25T05:31:44.95 10.0 positive automatic P 240 60.6103 0.554582 0.397953
II.MBAR.BHZ.00 2021-09-25T05:30:51.65 10.0 negative automatic P 9 53.0357 0.939542 0.499224
IU.SBA.BHZ.00 2021-09-25T05:30:05.10 10.0 positive automatic P 170 46.9077 1.15587 0.591837
IU.CASY.BHZ.00 2021-09-25T05:29:22.82 10.0 positive automatic P 143 41.6856 0.687057 0.698509
GE.VOI.BHZ. 2021-09-25T05:28:35.05 10.0 negative automatic P 38 36.0355 0.0573813 0.788164
G.FOMA.BHZ.00 2021-09-25T05:28:11.75 10.0 positive automatic P 41 33.3157 0.459752 0.881747
GE.WIN.BHZ. 2021-09-25T05:27:52.60 10.0 negative automatic P 348 31.1257 0.226871 0.928218
GT.LBTB.BHZ.00 2021-09-25T05:27:26.73 10.0 negative automatic P 4 28.3287 -0.771858 0.91954
GT.BOSA.BHZ.00 2021-09-25T05:26:54.68 10.0 negative automatic P 4 24.72 -0.301089 0.952381
AU.MAW.BHZ. 2021-09-25T05:26:42.00 10.0 positive automatic P 143 23.4342 -0.94658 0.963855
AF.ALKP.BHZ. 2021-09-25T05:26:41.67 10.0 negative automatic P 357 23.3809 -0.910244 0.8
GE.SNAA.BHZ. 2021-09-25T05:26:23.96 10.0 positive automatic P 202 21.6489 -0.185139 0.952381
II.SUR.BHZ.00 2021-09-25T05:26:18.42 10.0 negative automatic P 354 21.0166 0.913939 0.909091
AF.GRHM.BHZ. 2021-09-25T05:26:08.67 10.0 negative automatic P 7 20.1267 1.01244 0.930233
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