How to identified website is penalized?
 

If my website will panelized by Google then how to identify the cause which algorithm affect on?

Log into your webmaster account and search your message page from Google.look for a "you have been manually penalized" message or something similar.

If your website will panelized by Google, Google will send a message to you, It is possible you will not find your website when searching for certain keywords, visit decreased sharply, ...

Read about both algorithm Google PANDA and Google PENGUIN

To impose a penalty on (someone), as for breaking a law or rule
If your website is penalized, then Google will inform or warn you via email on your Google webmaster tool ID or message when you open your website Google webmaster tool.

Some identification of penalize
1. If your Keyword ranking is down day by day
2. Your Traffic is down
3. Not Index your website, check this search in google cache:yourdomainname. It show the date of Indexing.

If your Keyword is not coming on first page, then check your content and update it unique and fresh, informative

The main reasons can be that you will receive a message from google as mentioned above. You will probably lose your all keywords rankings and Page rankings. Hence lose in keywords ranking result in dropping of traffic also. So there are several reason behind it.

Basically, if your website was previously PR 4, and it dropped to no PR or N/A status, and you searched your website's domain using the site search operator, ex. site:yourdomain.com, but nothing comes up, there is a good chance that your website is penalized.