hi guys, i was surprised there was a chord tab for this but i think ive got it 
pretty accurately, although the ending/outro is a little off, please rate and put 
any corrections at the bottom! listen to the song to get the idea for the 
strumming pattern!

(any chords marked with a * play as an E-shaped barre chord)

Intro: E D | G D | E D | G E x2

E   | E   | E   | E (strum once) N.C

Verse
E           A                   C#m                
  Under the island, middle of a mountain
           E                A
There is a big bad, boomin' system
        C#m                   E 
Blowin' speakers, woofers and tweeters
     A             C#m
Amplifiers, melted wires
            E                     A
The parties exploded, the core is corroded
      C#m               E
Under ground, the Puget Sound
        A               C#m
Cause a shiftin', and a driftin'
            E                      A
A big black boom box, stuck in the hot rock
              C#m                    E
It's in there flowin', it's in there growin'
          A                     C#m
You don't believe me, that this scenery
          E
Could be a, cold blooded killer! 

Chorus
F#                           A*    N.C      A* | E A
  It's gonna blow, woah-woah-woah, Volcano!
F#                           A*    N.C      A* | E A
  It's gonna blow, Woah-woah-woah, Volcano!
F#                           A*    N.C      A* 
  It's gonna blow, Woah-woah-woah, Volcano!!

E D | G D | E D | G E x2

E   | E   | E   | E (Strum once) N.C

F                   A#                       Dm
  Now the island is shiftin', the plates are liftin'
            F                  A#
The core is creamy, docile and dreamy
               Dm
Stopped up and steamy
      F                          A#
Happy campers, are poopin' there pampers
         Dm                  F
When the mountain, becomes a fountain
             A#            Dm
Of white hot lava, molten magma
      F               A#
Super sonic, plate tectonics
       Dm               F
Stereo-phonic, lava and tonic
            A#           Dm
The boom is bionic, sony shut down
         F                   A#
Magnavox meltdown, ballistic breakdown
      Dm              F
Hi-fi heatwave, lo-fi lava cave
            A#              Dm
That sulfur smell is, Mt St Helens

Pompeii was yellin'!!
G*                           A#*   N.C      A#* | F A#
  It's gonna blow, woah-woah-woah, Volcano!
G*                           A#*   N.C      A#* | F A#
  It's gonna blow, woah-woah-woah, Volcano!
G*                           A#*   N.C      A#* | F A#
  It's gonna blow, woah-woah-woah, Volcano!
G*                           A#*   N.C     
  It's gonna blow, woah-woah-woah, Volcano!!

 GO!

F D# | G# F x2

(faster strumming) 

F D# G# F x4

F (N.C) | F    |


Thats it, you dont have to play the * chords as barre you can play them as open 
chords but i think it sounds better, please let me know any correcttions! cheers guys :D