From their Groundswell Album, Wave of Popular Felling.
Intro Part, basically the main rift.
Standard Tuning:
Lead: 
e|---------------------------------------------------------------------------|
B|---------------------------------------------------------------------------|
G|---------------------------------------------------------------------------|
D|3--(x2)6--(x2)--5--(x2)--8--(x3)-------------------------------------------|
A|1------4--------3--------6-------------------------------------------------|
E|---------------------------------------------------------------------------|

Rhythm: 
e|---------------------------------------------------------------------------|
B|---------------------------------------------------------------------------|
G|---------------------------------------------------------------------------|
D|1--------4--------3-------6------------------------------------------------|
A|1--(x2)--4--(x2)--3-(x2)--6--(x3)------------------------------------------|
E|1--------4--------3-------6------------------------------------------------|