Fate of the Lying Jade — John Newton Chance

In Spain, some twenty years after the war, Blake is trying to rescue a wayward daughter from trouble and return her to her politician father. But, after being trapped and shot at in a deserted village, with Blake in hot pursuit, the girl escapes to an equally deserted mine. There, exploration reveals a hoard of Nazi tat, including hideous busts and pornographic monstrosities. When diamonds are found hidden in the busts, the Germans and the Spanish converge on the mine to claim them. But then there is what appears to be an earthquake...