Honduras Tsunami on Jan. 10, 2018  


 

We have simulated the tsunami generated from the Honduras earthquake (17.469°N, 83.520°W, depth = 10.0 km, M = 7.6 at 02:51:31 UTC according to USGS) on January 10, 2018 (Fig. 1). The assumed tsunami source is located within the aftershock area (Fig. 1). The fault length and width are 40 km × 10 km. The focal mechanism is strike:75º, dip:82º, slip:-15º from the USGS's W-phase moment tensor solution. The top depth of the fault was assumed to 5 km. The average slip on the fault is 12 m. The seismic moment is 2.4 x 10**20 Nm (Mw = 7.5) assuming the rigidity of 5 x 10**10 N/m**2. As the initial condition for tsunami, static deformation of the seafloor is calculated for a rectangular fault model [Okada, 1985] using the source model. The used bathymetry data is the 30 arc-second grid data from GEBCO, which was resampled to 12 arc-second grid data. To calculate tsunami propagation, the linear shallow-water, or long-wave, equations were numerically solved by using a finite-difference method [Satake, 1995]. We have downloaded the Tide gauge data from UNESCO/IOC's web site, and compared the simulated tsunami waveforms and the observed ones (Fig. 2). We can see the tsunami propagation in Caribbean Sea and Gulf of Mexico (Fig. 3).


 

Fig.1 Tsunami Source Model

Fig.1 Tsunami Source Model
 The red lines indicate uplift with the contour interval of 0.2 m, while the blue dotted lines indicate subsidence with the contour interval of 0.2 m. Aftershocks determined by USGS are shown by red circles. The focal mechanism determined by USGS is also shown.


 

Fig.2 Maximum Height of Tsunami

Fig.2 Maximum Height of Simulated Tsunami and Tsunami Waveforms
 Solid lines in red and blue indicate the observed tsunami waveforms and synthtic ones, respectively.


 


Fig.3 Tsunami propagation

Fig.3 Tsunami Propagation (Click to start animation)
The red color means that the water surface is higher than normal sea level, while the blue means lower.


 

by Yushiro Fujii (IISEE, BRI) and Kenji Satake (ERI, Univ. of Tokyo)
 
 
References
Okada, Y. (1985), Surface Deformation Due to Shear and Tensile Faults in a Half-Space, Bull. Seismol. Soc. Am., 75, 1135-1154.
Satake, K. (1995), Linear and Nonlinear Computations of the 1992 Nicaragua Earthquake Tsunami, Pure and Appl. Geophys., 144, 455-470.


Last Updated on 2018/1/11