Mix paprika, cayenne, onion powder, salt, white pepper, black pepper, thyme, basil and oregano in a small bowl.
Brush salmon fillets on both sides with 1/4 cup melted butter and sprinkle evenly with the spice mixture. Drizzle one side of each fillet with half of the remaining butter.
Heat a large heavy skillet over high heat. Cook salmon butter-side down until blackened, 2-5 minutes. Turn, drizzle with remaining butter, and continue cooking until blackened and the fish flakes easily with a fork.