Heat the olive oil in a skillet over medium heat. Sprinkle pork on all sides with salt, pepper, and garlic powder, and lightly coat with cornstarch. Place pork in the skillet, and cook until lightly browned but not done. Transfer to a slow cooker. Place potatoes, carrots, celery, red bell pepper and onion in the slow cooker.
In a bowl, mix the tomatoes, cream of mushroom soup, broth, tapioca,and seasoning. Pour into the slow cooker.
Cover, and cook 1 hour on High. Reduce heat to Low, and continue cooking at least 3 hours.