Arrow styles in Cartesian coordinate system 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 PS=plot.ps PDF=plot.pdf R=0/10/0/10 J=X10i/7i gmt psbasemap -R$R -J$J -K -Bx1f0.1 -By1f0.1 -BWSen > $PS echo "1 1 0 2i" | gmt psxy -R -J -K -O -Sv1c+b >> $PS echo "1 2 0 2i" | gmt psxy -R -J -K -O -Sv1c+e >> $PS echo "1 3 0 2i" | gmt psxy -R -J -K -O -Sv1c+b+e >> $PS echo "1 4 0 2i" | gmt psxy -R -J -K -O -Sv1c+b+h1 >> $PS echo "1 5 0 2i" | gmt psxy -R -J -K -O -Sv1c+e+h1 >> $PS echo "1 5 0 2i" | gmt psxy -R -J -K -O -Sv1c+e+h1 -Gred >> $PS echo "1 6 0 2i" | gmt psxy -R -J -K -O -Sv1c+m -Gred >> $PS echo "1 7 0 2i" | gmt psxy -R -J -K -O -Sv1c+e+l -Gred >> $PS echo "1 8 0 2i" | gmt psxy -R -J -K -O -Sv1c+e+r -Gred >> $PS echo "1 9 0 2i" | gmt psxy -R -J -K -O -Sv1c+e+a90 -Gred >> $PS echo "5 1 0 2i" | gmt psxy -R -J -K -O -Sv1c+e+h-2 -Gred >> $PS echo "5 2 0 2i" | gmt psxy -R -J -K -O -Sv1c+e+h-1 -Gred >> $PS echo "5 3 0 2i" | gmt psxy -R -J -K -O -Sv1c+e+h2 -Gred >> $PS echo "5 4 0 2i" | gmt psxy -R -J -K -O -Sv1c+b+e+h0 >> $PS echo "8 1 0 1i" | gmt psxy -R -J -K -O -Sv1c+bt >> $PS echo "8 2 0 1i" | gmt psxy -R -J -K -O -Sv1c+bc >> $PS echo "8 3 0 1i" | gmt psxy -R -J -K -O -Sv1c+ba >> $PS echo "8 4 0 1i" | gmt psxy -R -J -K -O -Sv1c+bA >> $PS echo "8 5 0 1i" | gmt psxy -R -J -K -O -Sv1c+bi >> $PS echo "8 6 0 1i" | gmt psxy -R -J -K -O -Sv1c+bI >> $PS echo "5 5 2i 0 45" | gmt psxy -R -J -K -O -Sm1c+b+e+h1 -Gred>> $PS echo "5 7 2i 0 90" | gmt psxy -R -J -O -Sm1c+b+e+h1 -Gred >> $PS gmt psconvert -E150 -Tg -A -P $PS ps2pdf $PS $PDF evince $PDF rm $PS Vectors in geographic coordinate system 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 R=-100/100/-70/70 J=M7i PS=geo_arrow.

Boundary condition is necessary when we find the numerial solutions to some equations. Here, we show you some kinds of boundary contions in solving partial difference equation. 1 Dirichlet (fixed) $$ \left \{ \begin{aligned} p(t, x_{min}) &= 0\\ p(t, x_{max}) &= 0 \end{aligned} \right. \tag{1}, $$ where, $p(t, x)$ is what we want to find, let’s say, pressure in acoustic wave equation. 2 Neumann $$ \left \{ \begin{aligned} p(t, x_{min}) &= p(t, x_{min}+\Delta x)\\

New responses, if the wave field is diffuse, can be retrieved from interstaion cross-correlation of ambient noise. However, the cross-correlation time functions are asymmetric if the noise sources distribute unevenly. Here, we give you an example to show that how the cross-correlation functions vary with the angles of noise sources (red dots). We computed synthetic seismograms of earthquakes with angles from 1 to 360 degrees with an interval of 1 degree and data are recorded by two receivers (blue triangles); then we compute the cross-correlation time functions and align them with the angles; lastly, we stack all the cross-correlations to show you it’s symmetric under the condition that the noise sources distribute evenly.

Usually, we need to do back-projection from our back-azimuth $–$ slowness panel of body waves to geographic locations. We’ll obtain the location of some body phase if we know the ray parameter of the body phase of corresponding epicentral distance. Here, we show you how to calculate the ray parameters versus the epicentral distances using the python library obspy. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 from obspy.

Python is very convenient for us to develop a package. How to install your own python package and import it like numpy or other packages? Here, we’ll give a very simple example to you. 1 Prepare your python package Create a empty directory called whatever, and here we name it Lib_Hello. Now give a name to your python package and we call it HelloPackage, and in directory HelloPackage, implement a python module.