There are 17 Trophies that can be collected.

SILVER

This. is. SKATEBOARDING!
Win a match online

GOLD

Old School
Score 200,000 points without performing a single Manual in one run in Warehouse

Bringing home the bacon
Unlock Officer Dick

Manual Master
Perform 15 manuals in one combo in School II with Rodney Mullen

Gap Skiing
Complete the 100 Ski Jump gap in Downhill Jam

Ain't 'fraid of no ghosts
Collect all pellets in one combo in Hawkman in the Hangar

The Best, Around
Get 500,000 points in one run in Venice Beach

I don't want no 2 minute Man
Hold a combo for 30 seconds after the time is up in Marseille

Race to the finish lines
Reach the end of the Mall 3 times in a single Big Head Survival run

Completist
Complete all Projective s with one character

PLATINUM

Tony Hawk's PS Master
Unlock All Trophies

9 SECRET

BRONZE

School's Out
Unlock School II

Danger Zone
Unlock The Hangar

A Mall Rat
Unlock Mall

SILVER

Going Back to Cali
Unlock Venice Beach, CA

Da Jam
Unlock Downhill Jam

Uh huh, Oui Oui
Unlock Marseille, France

http://www.ps3trophies.org/game/tony-hawks-pro-skater-hd/trophies/