In a small bowl, mix paprika, cayenne pepper, onion powder, salt, white pepper, black pepper, thyme, basil and oregano.
Brush salmon fillets on both sides with 1/4 cup butter, and sprinkle evenly with the cayenne pepper mixture. Drizzle one side of each fillet with 1/2 remaining butter.
In a large, heavy skillet over high heat, cook salmon, butter side down, until blackened, 2 to 5 minutes. Turn fillets, drizzle with remaining butter, and continue cooking until blackened and fish is easily flaked with a fork.