Is Washington's Mount St. Helens going to blow again? This new documentary looks at scientific efforts to collect valuable information that might provide advance warning of a volcanic eruption, the last of which happened in 1980. "Feasting on Asphalt" (9 p.m., Food Network): Before people needed to conquer, build, shop and commute, they needed to eat. That's why there are roads -- at least, according to Alton Brown. So this intrepid culinary investigator hits the road with his motorcycle to find what's on the menu. "Feasting on Asphalt," which premieres tonight, is a four-episode series documenting Brown's quest. Loosely following Route 50, Brown and crew will meander from Savannah, Ga., across the bayous of Louisiana, over the hill country of Texas, across the high dusty dessert, then west to Las Vegas and the California coast. Brown ("Good Eats" and "Iron Chef America") will be eating on the go at every level, from foraging in the forest to hitting roadside diners -- not to mention churches, VFW halls, and homes of folks nice enough to offer a weary traveler a meal.