On September 9, 2010, about 6:11 p.m. Pacific daylight time, a 30-inch-diameter segment of an intrastate natural gas transmission pipeline known as Line 132, owned and operated by the Pacific Gas and Electric Company (PG&E), ruptured in a residential area in San Bruno, California. The rupture occurred at mile point 39.28 of Line 132, at the intersection of Earl Avenue and Glenview Drive. The rupture produced a crater about 72 feet long by 26 feet wide. The section of pipe that ruptured, which was about 28 feet long and weighed about 3,000 pounds, was found 100 feet south of the crater. PG&E estimated that 47.6 million standard cubic feet of natural gas was released. The released natural gas ignited, resulting in a fire that destroyed 38 homes and damaged 70. Eight people were killed, many were injured, and many more were evacuated from the area. Use ALOHA and MARPLOT to map the associated flammable zone (Hint: Use google maps to find the location, then search for it in MARPLOT). Assess the potential for explosion damage with time of explosion unknown. Print the text summary from ALOHA. If an explosion threat exists, include a screen shot of the MARPLOT map with the rings of overpressures superposed. You may assume the following (gleaned from the NTSB report):

a. The air temperature was 64 F and the wind was from northwest at 18 mph.

b. Ground roughness was open country, no cloud cover, and a relative humidity of 50%.

c. The pipe diameter was 30 inches and the pressure 11.2 km upstream was 400 psia.

d. The gas was methane (ALOHA does not have data for natural gas).

e. The inside of the pipe was rough (it was an old pipe).

f. The scenario is flammable gas escaping from pipe (but not yet not burning).