function [tppp, tpps, tpss, tsss]=modelling(h,vp1,vp2,vs1,vs2,offset)

icpp=asin(vp1/vp2);
icps=asin(vp1/vs2);
icss=asin(vs1/vs2);

tppp = (2*h*cos(icpp))./vp1 + offset/vp2;

tpps = (h*cos(icpp))./vp1 + (h*cos(icps))./vs1 + offset/vp2;

tpss = (h*cos(icps))./vp1 + (h*cos(icss))./vs1 + offset/vs2;

tsss = (2*h*cos(icss))./vs1 + offset/vs2;

tdp = offset/vp1;

tds = offset/vs1;