Warm the oil in a large saucepan or stockpot over medium-high heat. Add the onion, carrots, celery and, jalapeño and cook until tender but not brown, about 5 minutes.
Add the broth, wine, water, potatoes, thyme, and salt. Increase heat to high and bring to a boil. Reduce heat to medium and simmer, partially covered, 10 minutes.
Add the tomatoes and return to a boil. Stir in the scallops, shrimp, and clams. Cover and cook over medium-high heat, just until the scallops and shrimp turn opaque, about 7 minutes.