.. highlight:: rst .. _easywave2: ######### easywave2 ######### **EasyWave** Description =========== .. _toast_easywave: |ewname| simulates tsunami generation and propagation very rapidly and on the fly during runtime of |toast|. It supports computation on GPU resulting in a vast speed-up compared to CPU. |ewname| is thus very well suited for the application in |toast|. |ewname| is not part of |gss| (rights owner is Andrey Babeyko, GFZ German Research Center for Geosciences, Potsdam, babeyko@gfz-potsdam.de), but |gss| is delivered including |ewname| executables and a plugin acting as interface between |gss| and |ewname| (for simplicity also called |ewname| or `easywave2`). Configuration ============= |gss| uses |ewname| through a plugin which takes care of the generation of required input files for |ewname|, executes it with appropriate options and reads in the computed output. Several parameters for |ewname| can be configured using: :program:`scconfig` :menuselection:`--> Modules --> gempa --> easywave2 --> easywave2`. These parameters are stored in `~/seiscomp/etc/easywave2.cfg`. A description of the parameters can be found at the end of this section under *Configuration*. See also: :ref:`toast_forecast_zones_configuration`. .. _toast_bathymetry_files_configuration: Bathymetry files ---------------- (From TOAST Simulation bathymetry files configuration) In order for a tsunami on-the-fly-simulation to be computed (in contrast to a pre-computed scenario), a directory containing the bathymetry file(s) for the simulation backend has to be provided. In case of |ewname|, the directory is configured at :confval:`easywave2.data`. Example: .. code-block:: sh easywave2.data = /home/data/bathymetry/ You can use :ref:`gsm ` to install a set of bathymetry files for |ewname|: .. code-block:: sh sysop@host:~$ cd install/gsm sysop@host:~$ ./gsm install bathymetry See the GSS documentation on how to configure the default bathymetry for the simulations within a source region. .. _toast_creating_bathymetry: Creating bathymetry files ~~~~~~~~~~~~~~~~~~~~~~~~~ |gss| is provided with bathymetries suiting the needs of the customer. Additional bathymetry files for |ewname| can be made by the following procedure: - Generate and download a bathymetry grid in geotiff format from `NOAA Grid Extract `_: - Select *ETOPO1 (bedrock)* - Click on the icon *Select area of interest by rectangle* and use the mouse or enter the Area of Interest manually - Download Data - Convert the file to binary Surfer 6 grd format as used by |ewname| in two steps: - Use gdal software to convert the downloaded geotiff file to ArcGIS: - :code:`gdal_translate -of AAIGrid ` - Use the script |toastdata|/scripts/arc2grd.py to convert the ArcGIS file to binary surfer grid: - :code:`./arc2grd.py ` - move the surfer file to the bathymetry directory In case of |ewname|, the bathymetry has to be provided in *Golden Software Surfer 6* `binary `_ (preferred) or `text `_ format. .. _note-show_bathymetry: .. note:: To display the bathymetry which was used for a simulation in map view with color coding, select a simulation and click *Bathymetry* in the :ref:`toast_map_layers_panel`. Note that this works only for binary, not for text format grid files. To show the outline of a bathymetry file as green line, go to the :ref:`toast_backend_settings` in the interactive simulation dialog and select the respective bathymetry (grid). |ewname| executable internal technical description ================================================== .. note:: The generation of input files for |ewname| and the import of the computed results is handled by the |toast| |ewname| plugin, nevertheless we here give a description on how |ewname| is structured and works internally. Execute `~/seiscomp/bin/easywave2` to get additional information about |ewname| options. Tsunami source modeling ----------------------- There are two possibilities to set-up tsunami generation in |ewname|: #. Providing earthquake fault(s) parameters (as is done by |toast|) #. Providing the initial condition directly (sea floor deformation) Both source options assume instant sea-surface displacement. Time-dependent forcing is presently not implemented. #. Co-seismic displacement is modeled according to the classical Okada model (1985) for the uniform-slip rectangular rupture in a homogeneous half space. Any number of faults can be given in an input file which allows the user to simulate ruptures with complicated non-uniform slip distributions. There is no fixed set of input fault parameters in |ewname|. General rule - a fault should be sufficiently defined. For example, one can literally specify the whole set of Okada's parameters: location, depth, length, width, slip, strike-, dip- and rake-angle, or give fault location, orientation and earthquake moment magnitude. In the latter case, scaling relations (usually, Wells and Coppersmith, 1994) are implied to estimate rupture geometry and amount of slip. #. Alternatively, the initial condition can be directly given on the program input. In this case input 2D-map should be stored in text- or binary- Golden Software GRD-format. Wave propagation ---------------- |ewname| follows the computational algorithm presented in Kowalik and Whitmore (1991). Two-dimensional shallow water equations are solved on a staggered finite-difference grid in spherical coordinates implying explicit time-stepping. In |ewname| only linear approximation is considered, i.e., advection, bottom-friction and Coriolis terms are disabled (see General Description and Motivation above). The algorithm does not calculate coastal inundations and detailed run-ups directly. Instead, |ewname| brings the tsunami wave until the validity limit of the linear shallow water model (usually, 20-50 meter water depth) and then estimates run-ups with empirical relations (e.g., Chesley and Ward, 2006). Validation ---------- |ewname| has been compared to TUNAMI-N2 (Imamura, 1996), a widely used tsunami simulation software for a number of scenarios around the Indian Ocean. Leading, non-reflected waves show perfect coincidence till the very shallow (<10m) depths except for the cases when the leading wave travels long distances along the coast thus accumulating second-order shallow-water effects like bottom friction. In this case |ewname| showed somewhat earlier and lower-amplitude first arrival (the differences being still inside the tolerance of the early warning precision). Configuration files ------------------- An example for the main configuration file of |ewname| is tsunami.cfg and is listed below: :: ; TSUNAMI configuration file ; bathymetry file [bathymetry]= /home/data/bathymetry/C_e10_25e70s_120e33n.grd ; time step (for this bathymetry) [sec] [time_step]= 5 ; minimal calculatuional depth [m] [min_depth]= 20 ; Initial uplift: smoothing radius [grid-nodes] [ssh0_smooth]= 0 ; Initial uplift: relative threshold [0-1] [ssh0_rel_threshold]= 0.0 ; Initial uplift: absolute threshold [m] [ssh0_abs_threshold]= 0.1 ; Ssh clip threshold [m]: calculate only in region where ssh > threshold plus clip-rand [ssh_clip_threshold]= 1.e-4 ; Threshold for 2D-arrival time map [m] [ssh_arrival_threshold]= 0.0000001 ; Ssh clip rand [grid-nodes]: to give more space for wave propagation beyond actual wave front [ssh_clip_rand]= 3 ; progress output after each ... minutes [dt_out_progress]= 1 ; 2D field output after each ... minutes [dt_out_2D]= 1 ; Threshold for the ssh 2D-output transparency mask [m] [ssh_transparency_threshold]= 0. ; Always overwrite sshmax 2D output [1/0] [overwrite_sshmax]= 1 ; Points-Of-Interest (POIs) file [POIs_file]= poi.dat ; POIs output after each ... seconds [dt_out_POIs]= 15 ; POIs max shadow dist (if POI is on land) [km] [max_shadow_dist_POIs]= 100 [min_shadow_depth_POIs]= 0 .. note:: The configuration file tsunami.cfg is not used by the |toast| |ewname| plugin, as the parameters are passed as command line options. We list it nevertheless for reference. The configuration file when using |ewname| with |toast| is `~/seiscomp/etc/easywave2.cfg`. In addition to tsunami.cfg, |ewname| reads a POI configuration file named poi.dat and a GNSS file named gnss.dat. The latter one is used to compute displacements at GNSS stations. The format looks like this: :: BENO 115.217 -8.7666 1 CHRS 105.669 -10.4294 1 CHTT 91.825 22.3333 1 CILA 109 -7.75 1 CILI 109 -7.75 1 Output ------ |ewname| produces both 1D- and 2D-outputs. Wave time series can be stored for any given location in a simple text-table format. Optional run-up estimates are provided as well. Additionally, 2D outputs of the wave propagation are stored at regular time intervals as binary GRD-files (Golden Software grid file format). This 2D-output is compact since only part of the grid corresponding to the actual propagation area is written. Other 2D-outputs (also in binary GRD-format) contain maximum wave height and tsunami arrival times. The output directory is usually located at: `~/.seiscomp/gss/easywave2/output`. A typical simulation directory looks like this: :: `-- 83 `-- 004006S `-- 100102E `-- 83004006S100102E6543c67e7e4a0474c85e96bf11829851ee2ba6 |-- fault.inp |-- gnss.dat |-- gnss.dat.xyz |-- poi.dat |-- poi.dat.lst |-- protocol.txt |-- source.inp |-- tsunami.cfg |-- wave.2D.00000.ssh |-- wave.2D.00120.ssh |-- wave.2D.00240.ssh |-- wave.2D.00360.ssh |-- wave.2D.00480.ssh |-- wave.2D.00600.ssh |-- wave.2D.00720.ssh |-- wave.2D.00840.ssh |-- wave.2D.00960.ssh |-- wave.2D.01080.ssh |-- wave.2D.01200.ssh |-- wave.2D.01320.ssh |-- wave.2D.01440.ssh |-- wave.2D.01560.ssh |-- wave.2D.01680.ssh |-- wave.2D.01800.ssh |-- wave.2D.idx |-- wave.2D.sshmax |-- wave.2D.time |-- wave.patches |-- wave.poi.ssh `-- wave.poi.sshmax The first level corresponds to magnitude, the second to latitude, the third to longitude and then follows the unique simulation ID. The different file types contain the following information: \*.2D.\*.ssh are the sea level surface height grid files wave.2D.sshmax is the maximum sea level surface height grid file wave.2D.time is the arrival time grid file wave.patches contain the patch information wave.poi.ssh sea level surface height information wave.poi.sshmax contains POI ID, maximum sea level surface height and run-up wave.2D.idx contains output grid list Module Configuration ==================== | :file:`etc/defaults/global.cfg` | :file:`etc/defaults/easywave2.cfg` | :file:`etc/global.cfg` | :file:`etc/easywave2.cfg` | :file:`~/.seiscomp/global.cfg` | :file:`~/.seiscomp/easywave2.cfg` easywave2 inherits :ref:`global options`. .. note:: Modules/plugins may require a license file. The default path to license files is :file:`@DATADIR@/licenses/` which can be overridden by global configuration of the parameter :confval:`gempa.licensePath`. Example: :: gempa.licensePath = @CONFIGDIR@/licenses .. _easywave2: .. confval:: easywave2.arrivalTimesStep Default: ``15`` Unit: *min* Type: *int* Output interval of the arrival times grids in minutes. .. confval:: easywave2.binary Type: *string* EasyWave binary to execute. .. confval:: easywave2.contourThreshold Default: ``0.01`` Unit: *m* Type: *double* Contour lines with a maximum ssh value of this value are ignored. .. confval:: easywave2.data Default: ``@CONFIGDIR@/gss/easywave2/data`` Type: *string* Directory for input bathymetry grid files. All files found directly in this folder and ending on '.grd' are interpreted as bathymetry files. The first matching grid \(automatic calculation\) or the file selected \(interactive simulation\) is passed to EasyWave. .. confval:: easywave2.enableLogging Default: ``true`` Type: *boolean* Log console output of EasyWave process .. confval:: easywave2.forecastPoints Type: *list:string* Registration of forecast points. .. confval:: easywave2.gpu Default: ``false`` Type: *boolean* Use GPU for processing if supported .. confval:: easywave2.maxProcesses Default: ``1`` Type: *int* Maximum number of simultaneous processes started by this plugin. .. confval:: easywave2.maxTime Default: ``60`` Unit: *min* Type: *int* Maximum time span for which the tsunami propagation is calculated. .. confval:: easywave2.output Default: ``@CONFIGDIR@/gss/easywave2/output`` Type: *string* Base directory of EasyWave outputs. The results of a particular simulation are expected in a subfolder named after the eventID specified in EasyWave input file. .. confval:: easywave2.ruptureRatio Default: ``0.0`` Type: *double* Rupture length to width ratio .. confval:: easywave2.shadowPOIMinDepth Default: ``10`` Unit: *m* Type: *int* To simulate the tsunami wave for a POI the next water grid point is used. Only deep water points should be used. The minimum water depth can be defined here. .. confval:: easywave2.shadowPOIMaxDist Default: ``100`` Unit: *km* Type: *int* Distance in which the next water grid point is searched in case the POI is on land. .. confval:: easywave2.sshStep Default: ``15`` Unit: *min* Type: *int* Output interval of the ssh grids in minutes. .. confval:: easywave2.sshTracesStep Default: ``15`` Unit: *s* Type: *int* Output interval of the traces in seconds. .. confval:: easywave2.T1Threshold Default: ``0.01`` Type: *double* Threshold for the minimum detectable amplitude. See also T1Absolute. .. confval:: easywave2.T1Absolute Default: ``false`` Type: *boolean* If false, only exceedance of positive amplitude counts as detection. If true, also falling below negative amplitude counts. See also T1Threshold. .. _easywave2.forecastPoints: .. note:: **easywave2.forecastPoints.\*** *Define forecast point profiles.* *Register the profiles at 'forecastPoints'.* *Note that forecast zones have to be defined and registered* *in TOAST.* .. _easywave2.forecastPoints.$name: .. note:: **easywave2.forecastPoints.$name.\*** $name is a placeholder for the name to be used and needs to be added to :confval:`forecastPoints` to become active. .. code-block:: sh forecastPoints = a,b easywave2.forecastPoints.a.value1 = ... easywave2.forecastPoints.b.value1 = ... # c is not active because it has not been added # to the list of forecastPoints easywave2.forecastPoints.c.value1 = ... .. confval:: easywave2.forecastPoints.$name.filename Type: *string* Absolute filename of the forecast point file in dBase format .. _easywave2.patches: .. note:: **easywave2.patches.\*** *Configure settings for the automatic patches (rupture* *segments) generation.* .. confval:: easywave2.patches.dipAlign Default: ``0.5`` Unit: *0, 1* Type: *list:double* List of alignments in dip direction in range [0, 1]. 0.5: at hypocenter < 0.5: updip > 0.5: downdip 0,0.5,1 creates simulations centered at the upper and lower extend and at the hypocenter depth of the original rupture. .. confval:: easywave2.patches.length Default: ``100`` Unit: *km* Type: *int* Initial patch length .. confval:: easywave2.patches.strikeAlign Default: ``0.5`` Unit: *0, 1* Type: *list:double* List of alignments in strike direction in range [0, 1]. 0.5: at hypocenter > 0.5: with strike < 0.5: against strike 0,0.5,1 creates simulations centered at the far ends and over the hypocenter of the original rupture.