A name which seems to suit is:
I have searched for treasure in Egypt,
Santiago from Paulo Coelho's The Alchemist who travels to the pyramids looking for treasure.
and spent a lifetime fishing in the Atlantic.
Santiago, the title character Cuban fisherman of Hemingway's The Old Man and the Sea.
I have seen powerful storms form above me,
Santiago is a common place name in the Caribbean affected by hurricanes. Santiago City, Philippines has been hit by typhoons. (I think this answer needs to be more specific here.)
and felt the earth shaking with devastating effect.
Santiago, Chile, has suffered many devastating earthquakes, the largest being in 1647.
I have seen giant tortoises arrive and disappear.
Santiago Island in the Galápagos has had, and lost, populations of giant tortoises.
For a thousand years people have travelled to visit me.
Santiago de Compostela, destination of the Way of St. James, a pilgrimage route since the 9th C.