M 6.4 in Tonga on 23 Dec 2018 23:08 UTC

Hazard models

EQ parameters
Shakemap
Tsunami

Event summary

This earthquake is expected to have a low humanitarian impact based on the magnitude and the affected population and their vulnerability.

Earthquake Magnitude: 6.4M
Depth: 100.17 Km
Event Date: 23 Dec 2018 23:08 UTC
23 Dec 2018 11:08 Local
Exposed Population: Less then 100 people in MMI V
About 81000 people within 100km
Source: NEIC us2000iwvb
Inserted at: 23 Dec 2018 23:27 UTC
INFORM Coping capacity of the alert score:
4.6 (Tonga)

GDACS Score

For more info on GDACS alert score click here.
  Earthquake
(Shakemap)		 Tsunami GDACS score
NEIC 0 0 0
us2000iwvb Scaled population (vector) 0 Max wave alert 0m  
  C1 shakemap -0.59 Max wave realtime 0m  
  C2 shakemap 0.53      
  Country Vulnerability 0      
  INFORM_normalised 0.94      
Maximum expected impact using different data sources.
Click on image to zoom it.

Episode Timeline

IDAlertScoreDateMag, DepthMMI*Population**Tsunami risk***Delay (hh:mm)Source
1242337 0 23 Dec 2018 23:08 6.5M, 105.9km N/A 90 thousand (in 100km) 0m (at 00:00) 00:08 PTWC
1242341 0 23 Dec 2018 23:08 6.5M, 100km N/A 90 thousand (in 100km) 0m (at 00:00) 00:10 NTWC    
1242344 0 23 Dec 2018 23:08 6.4M, 100.17km 4.89 N/A (in MMI>=VII) 0m (at 00:00) 00:18 NEIC
The episode that generated the alert; the next major evaluations beyond 12 hours will not trigger additional alerts.
The episode that has the last updated information.
* The max MMI detected for sources having shakemaps;
** The population detected in MMI>=7 for episode with shakemap or in a 100km radius;
*** The tsunami max height.

Tsunami affected locations

Alert Date (UTC) Name Country Wave height (m)

See full locations list (RSS)


Initial conditions

Title: ""84km N of Nuku`alofa""

Fault parameters

  • Latitude: -20.375
  • Longitude: -175.092
  • Length: 25 km
  • Width: 7 km
  • Magnitude: 6.4 M

Okada parameters:

  • Slip: .6 m
  • Strike: 206 (geogr angle: north=0, south=180)
  • Dip: 32 degree
  • Rake: 90 degree
  • Depth: 100 km

Calculation parameters

  • Calculation space (lon/lat): -176.592, -21.875, -173.592, -18.875
  • Instead of Step -> use Cell size:.25 minutes

Sea Level

More information

  • Timeline:
    Tsunami calculations performed to this case, click here

For a full list of available products related to this event, please refer to the GDACS Resources page.