Istituto Nazionale di Geofisica e Vulcanologia

Earthquake with magnitude of Mw 8.1 on date 29-09-2009 and time 17:48:11 (UTC) in region Samoa Islands region [Sea: Samoa]

A magnitude Mw 8.1 earthquake occured in region: Samoa Islands region [Sea: Samoa], on

  • 29-09-2009 17:48:11 (UTC)
  • 29-09-2009 19:48:11 (UTC +02:00) Italian time
  • 29-09-2009 06:48:11 (UTC -11:00) local time in the region of the earthquake (Pacific/Apia)

and geographic coordinates (lat, lon) -15.4000, -172.1000 at 10 km depth.

The earthquake was located by: CSEM.

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

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
Locations history
Type Magnitude Date and Time (UTC) Latitude Longitude Depth (km) Published time (UTC) Author Location ID
Bulletin
Rev1000 		Mw 8.1 2009-09-29
17:48:11		 -15.4 -172.1 10 2013-01-05
18:33:13		 CSEM 970639
Preferred location and magnitude until now.
Origin information

Origin

Field Value
Time (UTC) 2009-09-29 17:48:11
Latitude -15.4000
Longitude -172.1000
Depth (km) 10 (from location)
Evaluation mode of Origin manual
Evaluation status of Origin reviewed
Version 1000 -> CSEM
Event type earthquake
Origin ID 970639

Uncertainty

Field Value
Preferred uncertainty description
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)
Confidence level of the uncertainty (%) 68

Quality

Field Value
Largest azimuthal gap in station distribution as seen from epicenter (degree)
Number of associated phases, regardless of their use for origin computation 31
Number of defining phases 23
RMS of the travel time residuals of the arrivals used for the origin computation (sec)
Epicentral distance of station closest to the epicenter (degree) 0.00000
Epicentral distance of station farthest from the epicenter (degree) 0.00000
Number of stations at which the event was observed 31
Number of stations from which data was used for origin computation 23
Magnitude information

Mw:8.1

Field Value
Value 8.1
Uncertainty
Num. used stations
Type of magnitude Mw
Reference to an origin 970639
Agency INGV
Autore CSEM
Time of creation (UTC) 2013-01-05 18:33:13
Picking and Arrival
SCNL Time Uncertainty Polarity Evaluation_mode Phase Azimuth Distance(km) Takeoff_angle Residual Weight
IV.BLLA.EHE. 2009-09-29T18:08:24.79 10.0 undecidable manual PKP 0 0 0
IV.TRTR.HHN. 2009-09-29T18:08:10.13 10.0 undecidable manual PKP 0 0 0
IV.HAVL.HHZ. 2009-09-29T18:08:08.20 0.1 undecidable manual PKP 0 0 0
IV.RESU.HHE. 2009-09-29T18:08:07.78 0.1 undecidable manual PKP 0 0 0
IV.HVZN.HHN. 2009-09-29T18:08:06.93 0.1 undecidable manual PKP 0 0 0
IV.GRI.EHE. 2009-09-29T18:08:05.61 10.0 undecidable manual PKP 0 0 0
IV.PLLN.SHN. 2009-09-29T18:08:04.25 0.1 undecidable manual PKP 0 0 0
IV.SENI.EHE. 2009-09-29T18:08:03.04 10.0 undecidable manual PKP 0 0 0
IV.NOVE.EHE. 2009-09-29T18:08:02.00 0.1 undecidable manual PKP 0 0 0
IV.CRAC.EHN. 2009-09-29T18:08:02.81 0.1 undecidable manual PKP 0 0 0
IV.NOCI.HHE. 2009-09-29T18:08:02.01 0.1 undecidable manual PKP 0 0 0
IV.PARC.HHE. 2009-09-29T18:08:01.54 10.0 undecidable manual PKP 0 0 0
IV.PALZ.HHZ. 2009-09-29T18:08:01.93 0.1 undecidable manual PKP 0 0 0
IV.MIGL.HHE. 2009-09-29T18:08:01.54 0.1 undecidable manual PKP 0 0 0
IV.SNAL.HHE. 2009-09-29T18:08:01.86 0.1 undecidable manual PKP 0 0 0
IV.INTR.HHN. 2009-09-29T18:08:01.04 0.1 undecidable manual PKP 0 0 0
IV.AOI.HHN. 2009-09-29T18:08:00.05 10.0 undecidable manual PKP 0 0 0
IV.RAVA.EHE. 2009-09-29T18:07:59.76 0.1 undecidable manual PKP 0 0 0
IV.FIU.EHE. 2009-09-29T18:07:59.12 0.1 undecidable manual PKP 0 0 0
IV.SGRT.HHE. 2009-09-29T18:07:59.88 0.1 undecidable manual PKP 0 0 0
IV.BADI.EHZ. 2009-09-29T18:07:59.09 0.1 undecidable manual PKP 0 0 0
IV.FNVD.HHN. 2009-09-29T18:07:58.76 1.0 undecidable manual PKP 0 0 0
IV.SACR.HHZ. 2009-09-29T18:07:58.06 10.0 undecidable manual PKP 0 0 0
MN.BNI.HHN. 2009-09-29T18:07:58.74 0.1 undecidable manual PKP 0 0 0
IV.ERBM.EHZ. 2009-09-29T18:07:58.49 0.1 undecidable manual PKP 0 0 0
IV.MRGE.HHE. 2009-09-29T18:07:57.68 0.1 undecidable manual PKP 0 0 0
IV.MSSA.HHE. 2009-09-29T18:07:57.50 0.1 undecidable manual PKP 0 0 0
IV.BRMO.HHE. 2009-09-29T18:07:57.83 0.1 undecidable manual PKP 0 0 0
MN.BLY.HHE. 2009-09-29T18:07:56.67 0.1 undecidable manual PKP 0 0 0
IV.APPI.EHZ. 2009-09-29T18:07:55.12 0.1 undecidable manual PKP 0 0 0
IV.FVI.HHE. 2009-09-29T18:07:53.36 10.0 undecidable manual PKP 0 0 0
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