Land by crashing into sea (7)
I believe the answer is:
estonia
'land' is the definition.
(I've seen this before)
'crashing into sea' is the wordplay.
'crashing' indicates an anagram.
'into'+'sea'='intosea'
'intosea' is an anagram of 'ESTONIA'.
'by' acts as a link.
(Other definitions for estonia that I've seen before include "Republic in the Baltic region, once part of USSR" , "Nation" , "European country, capital Tallinn" , "So eat in about here in Northern Europe" , "Baltic state" .)