Why would you do this? Here’s four possible reasons:
1. You may have submitted a new sitemap with hundreds (or thousands) of pages referenced in it.
2. You may have used the Fetch as Googlebot command and selected the ‘Crawl this URL and all directly connected URLs’ option.
3. Your site may be getting hits from spam links or spam pages
4. Your site may be hacked and spamming out URLs
There may be other instances that I have neglected to mention, but suffice to say any sudden flurry of activity should be investigated.
Read my article about why you should or shouldn’t change your crawl rate in Google Search Console.
