Which word is the head of the phrase "somewhere there"?

Question

Robocop's catchphrase is

somewhere there is a crime happening

If the sentence was just a crime is happening it would be unproblematic for me: a crime would be a noun phrase in the function of a subject, is happening would be a verb phrase in the function of a predicate.

Now in somewhere there, both words are adverbs , so it has to be an adverb phrase and it's function is a subject.

My problem is which of them is the head of the adverb phrase, because both appear to me as if they could.

remark

As it turned out , my question is based on wrong assumptions somewhere there in somewhere there is a crime happening is not a phrase.

Answer 1

Somewhere there is a crime happening.

In the sentence above from the Robocop films the word somewhere is functioning as a Locative Adjunct. Notice that it can appear either at the beginning or end of the clause:

• There is a crime happening somewhere.

Notice also that the word there cannot move with the word somewhere:

• *Is a crime happening somewhere there.

This suggests that the word there is not part of this Locative Adjunct. If we look at the sentence above, it is easy to see that the main reason it is ungrammatical is because it does not have a Subject. This is because in the original example, the word there IS the Subject of the sentence as the data below indicates:

• There is a crime happening
• Is there a crime happening?
• There is a crime happening, isn't there?
• There is!

The second example above shows there inverting with the auxiliary verb to form a question, as a good Subject should. The third example shows the word there appearing in the question tag isn't there as we would expect (compare with He's happy, isn't he?) The fourth example shows the sentence reduced to a minimal Subject and Predicate. Because the word is constitutes the Predicate, the word there must be the Subject.

In response to the Original Question then, the answer is that somewhere and there do not form a phrase in this sentence, and therefore neither one of them can be the Head of that phrase. Somewhere is functioning as Locative Adjunct, whereas there is functioning as Subject.

Answer 2

Edit: As Araucaria pointed out, OP (and consequently I) misinterpreted the sentence for Somwhere there a crime is happening/Somehwere there, there is a crime happening, which, however, is not what the sentence says; so my below answer only applies to the other assumption, not to the original sentence.

I would argue that there is the head for the following reasons:

• It is semantically more prominent: the information that projects is that the crime happend there, and somewhere somewhat relativizes the specificness of this local information, but the crime still happend there and not just somewhere. So somewhere would be a modifier to there rather than there adding more information about somehwere, because the phrase as a whole has the meaning that the crime happend there.
• I can't think of a case where in English the head of the adverb phrase precedes its adverbal modifiers - nested adverb structures, just like adjective sturctures, are to my knowledge always left-branching, i.e. the modifiers occur to the left, so if the head was somehwere while the modifier is there, this would be a very unusual exception to this general pattern.