# Tsunami Modeling and Satellite-Based Emergency Mapping: Workflow Integration Opportunities
## 2 Materials and Methods: Tsunami Modelling and Satellite-Based Emergency Mapping
### GDACS Tsunami Model Outputs  
The event timeline shown in Figure 3 highlights that several re-runs of the tsunami model were carried out (with a delay in the range of a few minutes to ~2 h), depending on the availability of more precise earthquake parameters. For this reason, the type of alert ranges from orange to red and the tsunami impact (in terms of max height) increases from 1.8 m to 7 m.  
Although GDACS is an automatic system and all the estimations are based on event detection and launch of dedicated calculations, the last value of the impact estimation (which is used as reference in this contribution) has been obtained by performing manual calculation \(\sim\)2 h after the event, when more precise information on the fault mechanism were available from USGS ([[http://earthquake.usgs.gov/earthquakes/eventpage/us20003k7a](http://earthquake.usgs.gov/earthquakes/eventpage/us20003k7a)]([http://earthquake.usgs.gov/earthquakes/eventpage/us20003k7a](http://earthquake.usgs.gov/earthquakes/eventpage/us20003k7a))), as detailed in Tables 2 and 3. Figure 3: Timeline of Global Disaster Alert and Coordination System (GDACS) episodes for the 2015 event in Chile. The various estimations are provided by different seismological organizations (as detailed in the Source field). Where available the maximum intensity estimated through the shakemap model by the United States Geological Survey (USGS) in Modified Mercalli Intensity (MMI) scale is also reported. Population is related to the number of people living in a radius of 100 km. * The max MMI is indicated when the shakemap is available. ** The population indicated here is the amount of people within the MMI larger than 7 for episodes where shakemap is available; when shakemap is not available the people in a 100 km radius is indicated. *** The tsunami max height is summarized as Tsunami risk; many more details are present min the detailed pages of GDACS. Figure 2: Comparison between a standard earthquake activation timeline and one based on early-tasking (very high resolution (VHR) optical imagery is acquired at approximately 10 am local time due to the use of sun-synchronous orbits. Image request cut-off times are different for each satellite data provider. Times for producing the 1 st damage assessment reflect the default delivery times of 12 h. Actual production times strongly depend on the size of the affected area and the density of assets at risk). Table 4 reports the list of the first 20 locations reached by the Tsunami wave according to the outputs of the tsunami model run. The full list of location is available at the GDACS website (see [[http://www.gdacs.org/report.aspx?eventtype=EQ&eveentid=1065792](http://www.gdacs.org/report.aspx?eventtype=EQ&eveentid=1065792)]([http://www.gdacs.org/report.aspx?eventtype=EQ&eveentid=1065792](http://www.gdacs.org/report.aspx?eventtype=EQ&eveentid=1065792))). The estimated maximum height is 7.0 m in Chigualoco (31.75\({}^{\circ}\) S, 71.50\({}^{\circ}\) W) but many other locations were estimated to have been severely impacted by the tsunami wave, as shown in Figure 4.  
In the analysis the GEBCO 30 s bathymetry has been used: in the coarse calculation (Figure 4a) the original GEBCO bathymetry was resampled at 1.75 min (3.5 km) while in the more refined calculation (Figure 4b) a down sampling to 0.25 min was adopted. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameter** & **Value** & & \\ \hline Displacement & 6 & (m) & \\ Width & 62 & (km) & \\ Length & 223 & (km) & \\ Strike & 353 & (deg.—North = 0 deg.) & \\ Dip & 19 & (deg.) & \\ Rake & 83 & (deg.) & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Fault geometry. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Arrival Time (UTC)** & \begin{tabular}{c} **Date/Time of Max** \\ **Height (UTC)** \\ \end{tabular}  & **Location** & \ \begin{tabular}{c} **Height** \\ **(m)** \\ \end{tabular}  & \begin{tabular}{c} **Lat/Lon** \\ **(WGS84)** \\ \end{tabular}