**Taken from Gamefaqs.com....hope this helps.
At The Dalmasca Westgate, look for a Bangaa (or a fat
monster), by the name of Rimzat. Try to talk to Bangaas you find in the area
to find him. He'll ask if you will gather information on sandstorms, and
agree to help him. Go to the fountain found in the "southern middle" part of
The Royal City of Rabanstre and look for a man sitting in the fountain by the
name of "Cotze". He'll tell you to go to Lowtown to find his friend. Look
for a man named "Northon", in the same section as where you can enter The
Garamsythe Sewers. He'll explain how he had an item that allowed them to
enter a sand storm, but they broke it into two different pieces so it
wouldn't be stolen by thieves.
The full item is called the Windvane, but Northon hid his half of the
Windvane under a dynast cactus, one of those big thick cacti you find
around the Dalmasca Westersands. Talk to Northon and he'll state how he hid
his half in the area "Shimmering Horizons", in the northwestern part of the
area. Rent a Choboco if you're in a rush, and head there.
There will be two dynast cacti in the area, go north and look for a cactus
there. Examine it and you should get Northon's half of the Windvane, the
Wind Globe. Quickly head back to the Westgate and you'll see that the three
people have meet together. Cotze should give you his half, and you'll get
the Windvane. Now, using this Windvane you can enter fierce sand storms.
You can now go to the area to fight The Earth Tyrant. There are two ways to
get to "The Wyrm's Nest" in the Westersands. Either go to the Dalmasca
Westersands, and head Northeast to eventually reach the area. Or, you may
go through the Dalmasca Estersands, take the ferry to the northern part of
The Damasca Estersands, and head northwest to get to the area where The
Earth Tyrant roams. Now, you can actually fight him. Be sure to save your
game in case you're unprepared. Don't want to go through this annoying
side quest again.
