Where is Diagnostics & Usage Data stored on iOS? Since I've installed a few jailbreak tweaks, my iPhone has been crashing fairly regularly and I would like to know exactly what's causing it.

Does anyone know the direct path to where the crash logs/reports are stored on the device (/var/mobile/, for example)? This way I can clear all current logs, to start afresh, and I can extract them for viewing on a bigger screen, etc. Or does anyone know of a more advanced way to interact with and analyse the iPhone's Diagnostics &amp; Usage data, in general?

Thanks
The official logs and crash logs in on the path
/var/mobile/Library/Logs. 
You can also download syslog. And get his logs from /var/syslog