Search alerts in SharePoint 2013 allow end-users to get an Email notification when specified search results are changed or updated. Search alerts will be enabled when we want to allow end-users to create alerts for search queries. Search alerts configured on the search query page when search query completed and results are displayed. Search alert are created only per-user and configurable and viewable to users who creates them. By default search alerts will be enabled.
Following are procedure to Enable/Disable search alerts.
Go to Central Administration -> Application Management -> Manage Service Applications
On the Manage Service applications page, click on the search service application to configure search alerts.
On the Search Administration page, In System Status section, check Search alerts status
We can see search alerts status as Off Enable or On Disable. By default alerts will be turned On. Click on Disable to turn off alerts or click on Enable to turn on the alerts.
Search alerts will be sent only if outgoing mails are configured and to configure search alerts for search queries that to run. To configure search alerts for search queries, users can click on the Alert Me link that located on the bottom of the search results page.