function [VBR,HF] = CB_010_depthProfiles()
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [VBR,HF] = CB_010_depthProfiles()
%
% Calculate seismic properties for a half space cooling profile at 30 Myrs
% Assumes constant density for thermal profile (analytical half space
% cooling), re-calculates density for the seismic properties.
%
% Output
% ------
% VBR the VBR structure
% HF halfspace model structure
% figures to screen
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% put VBR in the path %%
path_to_top_level_vbr='../../';
addpath(path_to_top_level_vbr)
vbr_init
%% build thermal model %%
HF = HalfspaceModel(30); % analytical half-space cooling
HF = correctHF(HF); % adjust solution (variable density, etc.)
[Solidus] = SoLiquidus(HF.P,5,0,'katz');
Tsolidus_C=Solidus.Tsol;
%% Load and set VBR parameters and stave variables %%
VBR.in.elastic.methods_list={'anharmonic';'anh_poro'};
VBR.in.viscous.methods_list={'HK2003'};
VBR.in.anelastic.methods_list={'eburgers_psp';'andrade_psp';'xfit_mxw'; 'xfit_premelt'};
VBR.in.elastic.anharmonic=Params_Elastic('anharmonic'); % unrelaxed elasticity
VBR.in.elastic.anharmonic.Gu_0_ol = 75.5; % olivine reference shear modulus [GPa]
VBR.in.SV.f = [0.01, 0.02, 0.04, 0.1];% frequencies to calculate at
% store thermal model in VBR state variables
VBR.in.SV.T_K = HF.T_C+273; % set HF temperature, convert to K
VBR.in.SV.P_GPa = HF.P/1e9; % pressure [GPa]
VBR.in.SV.rho=HF.rho; % density [kg m^-3]
VBR.in.SV.chi=HF.chi;
% set the other state variables as matrices of same size
sz=size(HF.T_C);
VBR.in.SV.sig_MPa = 10 * ones(sz); % differential stress [MPa]
VBR.in.SV.Tsolidus_K = Tsolidus_C+273;
VBR.in.SV.phi = 0.01 * (HF.T_C > Tsolidus_C); % melt fraction
VBR.in.SV.dg_um = 0.01 * 1e6 * ones(sz); % grain size [um]
%% CALL THE VBR CALCULATOR %%
[VBR] = VBR_spine(VBR) ;
%% Build figures %%
figure('PaperPosition',[0,0,14,4],'PaperPositionMode','manual')
ax1=subplot(1,5,1);
plot(HF.T_C,HF.z_km)
hold on
plot(Tsolidus_C,HF.z_km,'--k')
xlabel('T [C]')
ylabel('Depth [km]')
set(gca,'ydir','reverse')
ax2=subplot(1,5,2);
plot(HF.P/1e9,HF.z_km)
xlabel('P [GPa]')
ylabel('Depth [km]')
set(gca,'ydir','reverse')
ax3=subplot(1,5,3);
plot(HF.rho/1e3,HF.z_km)
xlabel('\rho [g/m3]')
ylabel('Depth [km]')
set(gca,'ydir','reverse')
for imeth = 1:numel(VBR.in.anelastic.methods_list)
meth=VBR.in.anelastic.methods_list{imeth};
ax4=subplot(1,5,4);
hold all
plot(squeeze(VBR.out.anelastic.(meth).V(:,1))/1e3,HF.z_km,'displayname',meth)
xlabel('ave. Vs [km/s]')
ylabel('Depth [km]')
xlim([4.2,4.7])
box on
set(gca,'ydir','reverse')
ax5=subplot(1,5,5);
hold all
plot(squeeze(log10(VBR.out.anelastic.(meth).Q(:,1))),HF.z_km,'displayname',meth)
xlabel('log10(Q)')
ylabel('Depth [km]')
box on
set(gca,'ydir','reverse')
xlim([0,8])
end
saveas(gcf,'./figures/CB_010_depthProfiles.png')
end
function HF = HalfspaceModel(age_Myrs)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% HF = HalfspaceModel(age_Myrs)
%
% Half Space Cooling Model, analytical solution
% T(z,t)=T_surf + (T_asth - T_surf) * erf(z / (2sqrt(Kappa * t)))
%
% Parameters
% ----------
% age_Myrs plate age in Myrs
%
% Output
% ------
% HF half-space cooling structure with settings and variables
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% HF settings %%
HF.Tsurf_C=0; % surface temperature [C]
HF.Tasth_C=1350; % asthenosphere temperature [C]
HF.V_cmyr=8; % half spreading rate [cm/yr]
HF.Kappa=1e-6; % thermal diffusivity [m^2/s]
HF.rho=3300; % density [kg/m3]
HF.t_Myr=age_Myrs; % seaflor age [Myrs]
HF.z_km=transpose(linspace(0,200,50)); % depth [km]
%% HF calculations %%
HF.s_in_yr=(3600*24*365); % seconds in a year [s]
HF.t_s=HF.t_Myr*1e6*HF.s_in_yr; % plate age [s]
HF.x_km=HF.t_s / (HF.V_cmyr / HF.s_in_yr / 100) / 1000; % distance from ridge [km]
%% calculate HF cooling model T profile %%
HF.dT=HF.Tasth_C-HF.Tsurf_C;
HF.erf_arg=HF.z_km*1000/(2*sqrt(HF.Kappa*HF.t_s));
HF.T_C=HF.Tsurf_C+HF.dT * erf(HF.erf_arg);
end
function HF = correctHF(HF)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% calculates a better density profile, adds on adiabat to temp
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
HF.dTdz_ad = 0.5 * 1e-3; % adiabat deg C/m
HF.T_C = HF.T_C + HF.dTdz_ad*HF.z_km*1e3;
HF.Z_moho_km = 20; % Moho depth [km]
HF.rhos_olv = 3300; % solid density [kg/m3]
HF.rhos_crust = 2800; % crustal density [km/m3]
% thermal properties at reference state
HF.Kc_olv = 4.17; % thermal conductivity [W/m/K], from Xu et al (see MaterialProperties.m)
HF.Kc_crust = 2; % thermal conductivity [W/m/K]
HF.Cp_olv = 1100; % heat capacity [J/kg/K]
HF.Cp_crust = 800; % heat capacity [J/kg/K]
fldz={'rhos';'Kc';'Cp'};
for ifl = 1:numel(fldz)
fld=fldz{ifl};
HF.(fld) = HF.([fld, '_olv'])* ones(size(HF.z_km));
HF.(fld)(HF.z_km<HF.Z_moho_km)=HF.([fld, '_crust']);
end
P0=1e5; % surf pressure, [Pa]
z=HF.z_km*1e3;
T_K=HF.T_C+273;
[rho,cp,kc,P] = ThermodynamicProps(HF.rhos,HF.Kc,HF.Cp,T_K,z,P0,HF.dTdz_ad,'PT_dep');
HF.rho=rho;
HF.P=P;
HF.chi=HF.z_km>HF.Z_moho_km;
end
