Early-est:     Southern Sumatra, Indonesia    2026.08.18-06:02:26.05    q:A      mb:5.3    Mwp:5.7*    Mwpd:-    Td*T50Ex:0.5     fmamp_polarity:./hypo.1787032944890.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1787032944890.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1787032944890.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: 5.3 [48]    Mwp: 5.7* [9]    Mwpd: 5.9Xinv [9]
Region: Southern Sumatra, Indonesia
Origin Time: 2026.08.18-06:02:26.05 UTC
Hypocenter: lat: -0.41°  lon: 98.65°  [+/-16km]    depth: 30km  [+/-20km]
Location Quality: qualityCode:  A     stdErr: 1.6s   assocPhases: 104   usedPhases: 58
minDist: 2.0°   maxDist: 159.0°   AzGap: 62°   2ndAzGap: 71°   atten: -1.86 [+/-0.22]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 11km   maxHorUnc: 16km   azMaxHorUnc: 49°
68%ConfEllipsoid:   semiMajorAxisLength: 22km   majorAxisAzimuth: 42°   majorAxisPlunge: 46°   semiIntermediateAxisLength: 18km   intermediateAxisAzimuth: 243°   intermediateAxisPlunge: 42°   semiMinorAxisLength: 13km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.5 [45]    Td: 1.0s [12]    Td*T50Ex: 0.5 [12]    To: 28.2s [44]
Closest plate boundaries:
   Sunda / Australia [subduction zone]: distance: ~130km
Subduction geometry:    Zone: Sumatra-Java: 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 (130km)
 no
 no
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   0.5
   0.5
   0.5
Td*To:
     28.2
     28.2
     28.2
Mwp magnitude:
       5.7*
       5.7*
       5.7*
Hypocenter depth:
       30km
       30km
       30km
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.1787032944890.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):
Nodal Plane 1: strike: 195°   dip: 59°   rake: 37°
Nodal Plane 2: strike: 84°   dip: 59°   rake: 143°
Quality: azimuthalGap: -1°   stationPolarityCount: 44   misfitWeightCount: 12.6   misfit: 0.11   stationDistributionRatio: 0.48   meanDistP: 24.5   meanDistT: 31.1   qualityCode: B
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1787032944890.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.1787032944890.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):
Nodal Plane 1: strike: 83°   dip: 61°   rake: 143°
Nodal Plane 2: strike: 193°   dip: 59°   rake: 34°
Quality: azimuthalGap: 68°   stationPolarityCount: 44   misfit: 0.26   stationDistributionRatio: 0.76   rmsAngDiffAccPref: 18.62   fracAcc30degPref: 0.94   qualityCode: B
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1787032944890.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1787032944890
Event info last updated: 2026.08.18-06:56:00 UTC
Event first association/location: 2026.08.18-06:06:01 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA