My dictionary says 罠にかかる but I imagine that that is for snares. How would you
say trapped as in "I am trapped under rubble" or "The people were trapped
under a building."?
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2017-01-28T11:26:45.490
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2017-01-29T04:46:48.283
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translation
How to say "trapped" in Japanese
（罠に）かかる is as you said appropiate for snares. You could use 閉じ込める (active). So
if you were trapped under rubble you can use passive form:

> がれきの中に閉じ込められた。
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2017-01-28T11:38:20.873
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2017-01-28T11:38:20.873
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Well with your example I would say this,

"trapped under rubble" = 瓦礫{がれき}の下に生{い}き埋{う}めとなった

The emphasis on "生{い}き埋{う}め" being the key phrase for trapped (buried) under
some rubble. Which means you are literally trapped alive under rubble, or say
for example a buildings rubble.

You also have something like this,

"I was trapped in a room" = 部屋{へや}に閉{と}じ込{こ}められた

Which has the emphasis on the 閉{と}じ込{こ}める
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2017-01-28T12:19:14.230
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2017-01-28T12:24:45.993
2017-01-28T12:24:45.993
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The phrase "trapped under" can be rendered as "～の下敷（したじ）きになる/なった".

So, one way of translating "I am trapped under rubble" is "がれきの下敷きになった".
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2017-01-29T04:46:48.283
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2017-01-29T04:46:48.283
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