How does a redirect effect SEO

I'm trying to optimize a site where when you type in the URL the only thing the index page is for is to redirect you to the /shop folder.

For instance when I type in www.someurl.com,behind the scenes I get redirected to www.someurl.com/shop

I'm curious how this effects SEO. Google's analytics shows 80% of my traffice comming direct while the third on the referral list is comming from my base url. So it looks like I'm referring traffic to myself.

All thoughts appreciated.

 

can you explain why you are redirecting in such matter?? can't you put those content oh index.html page??
even if you are doing redirection than do 301 redirect for that page. it wont affect seo thing for your site. but batter you put this page on index.html page..

 

I don't understand the thought process in redirecting anyway. I just took this over for a client to help boost traffic and get a higher SERP in google.

The redirect is done in Javascript as such:
<SCRIPT LANGUAGE="JavaScript">
<!-- Begin
redirTime = "10";
redirURL = "http://www.someurl.com/shop/index.php";
function redirTimer() { self.setTimeout("top.location.href = redirURL;",redirTime); }
// End -->
</script>

When the body loads it calls this redirTimer function

 

Really strange why are u re-directing the site to the shop folder. In that case just use a simple 301 re-direct ! may be that will help.

 

Before there were issues regardng supplemental or duplicate content results, but I don't know now because as of now I never see supplemental results in SERP anymore

 

I think you should read this one in regards to your query buddy http://www.mattcutts.com/blog/seo-mistakes-sneaky-javascript/