Early-est:     Tonga Islands    2026.03.29-23:45:11.30    q:C      mb:5.2*    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1774827919464.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1774827919464.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1774827919464.mech.hash.thumb.jpg

Automatic solution - this event has not been reviewed by a seismologist
Automatically determined event information may be incorrect!

Earthquake Details:
Magnitude: mb: 5.2* [37]    Mwp: 4.9X [1]    Mwpd: - [0]
Region: Tonga Islands
Origin Time: 2026.03.29-23:45:11.30 UTC
Hypocenter: lat: -16.38°  lon: -173.36°  [+/-31km]    depth: 15km  [+/-71km]
Location Quality: qualityCode:  C     stdErr: 2.5s   assocPhases: 84   usedPhases: 63
minDist: 2.9°   maxDist: 151.0°   AzGap: 55°   2ndAzGap: 72°   atten: -2.25 [+/-0.22]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 22km   maxHorUnc: 31km   azMaxHorUnc: 163°
68%ConfEllipsoid:   semiMajorAxisLength: 72km   majorAxisAzimuth: 184°   majorAxisPlunge: 80°   semiIntermediateAxisLength: 37km   intermediateAxisAzimuth: 339°   intermediateAxisPlunge: 9°   semiMinorAxisLength: 27km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.2 [28]    Td: 1.6Xs [2]    Td*T50Ex: - [0]    To: 1.9s [28]
Closest plate boundaries:
   Tonga / Pacific [subduction zone]: distance: ~110km
   Tonga - Niuafo'ou [continental rift boundary]: distance: ~130km
   Pacific - Tonga [oceanic transform fault]: distance: ~200km
Subduction geometry:    Zone: Kermadec-Tonga: DEBUG: error: [Errno 2] No such file or directory: 'gmt'    Slab depth at epicenter: error: evaluating slab depth: -999.9
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 YES (110km)
 no
 no
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   -
   -
   -
Td*To:
     -
     -
     -
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       15km
       15km
       15km
Slab depth at epicenter:
       n/a
       -
       -
Tsunami and Rupture predictions (TEST!): No prediction: Event too small (Mwp<7.0) or too few Mwp readings (N<20)
./hypo.1774827919464.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 161°   dip: 69°   rake: -16°
Nodal Plane 2: strike: 257°   dip: 75°   rake: -158°
Quality: azimuthalGap: -1°   stationPolarityCount: 36   misfitWeightCount: 6.6   misfit: 0.15   stationDistributionRatio: 0.35   meanDistP: 51.2   meanDistT: 53.2   qualityCode: D
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1774827919464.mech.fmamp_polarity.mechanism.jpg
First-motion Focal Mechanism (FMAMP_POLARITY_WAVEFORM):    (No solution available)
Nodal Plane 1: strike: 0°   dip: 0°   rake: 0°
Nodal Plane 2: strike: 270°   dip: 90°   rake: 90°
Quality: azimuthalGap: -1°   stationPolarityCount: 0   misfitWeightCount: -1.0   misfit: -1.00   stationDistributionRatio: -1.00   meanDistP: -1.0   meanDistT: -1.0   qualityCode: X
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity_waveform
./hypo.1774827919464.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):
Nodal Plane 1: strike: 97°   dip: 81°   rake: 175°
Nodal Plane 2: strike: 188°   dip: 85°   rake: 9°
Quality: azimuthalGap: 89°   stationPolarityCount: 36   misfit: 0.33   stationDistributionRatio: 0.65   rmsAngDiffAccPref: 15.78   fracAcc30degPref: 0.98   qualityCode: B
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1774827919464.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1774827919464
Event info last updated: 2026.03.30-00:44:00 UTC
Event first association/location: 2026.03.29-23:50:01 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA