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> 私は地震が怖い。

For me that's like saying 私は彼がきれいです.  
It doesn't make sense putting 私 here.
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2018-02-19T11:56:34.167
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grammar translation particle-は particle-が
Does 私は地震が怖い make sense?
While it may be _redundant_ , using `私は` certainly does make sense here and
may even be necessary in some contexts to avoid ambiguity. A somewhat
contrived example:

```

    彼は幽霊{ゆうれい}屋敷{やしき}は苦手{にがて}、私は地震が怖い。 
    He doesn't like haunted houses, and I'm afraid of earthquakes.
    
```

Your second example is indeed somewhat nonsensical but is not equivalent to
the first.
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> 私は地震 **が怖い** 。 _lit._ As for me, earthquakes are scary. → I _am scared of_
> earthquakes.

Your sentence is correct and natural.

が is used with several adjectives that indicate one's feelings, e.g.
「怖い」「欲しい」「つらい」「楽しい」「恐ろしい」「悲しい」「うれしい」「うらやましい」「憎い」「愛しい」 (i-adjectives) 「好きだ」
「嫌いだ」「いやだ」「心配だ」「面倒だ」「楽しみだ」 (na-adjectives) etc.

Examples:

> 「僕は自転車 **が欲しい** 。」 I _want_ a bicycle.  
>  「私は日本語の勉強 **が楽しい** 。」 I _enjoy_ learning Japanese.  
>  「山田さんはコーヒー **が好き** だ。」 Yamada-san _likes_ coffee.

が is also used with the desiderative auxiliary 「～たい」. eg 「私はコーヒー **が** 飲み
**たい** 。」 I _want to_ drink coffee.
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2018-02-19T13:25:41.147
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私は地震が怖い makes sense and the user "Chocolate" has given a very good
explanation.

Other ways to express the fear of earthquakes could be:

地震が怖いんだよ。I'm telling you, earthquakes are scary.

地震は私の一番恐怖です。Earthquakes are my biggest fear.

地震はとても恐ろしいと思います。I think earthquakes are very scary.

地震の時パニクりた。I panicked at the time of the earthquake.
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2018-02-20T04:46:17.377
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answer