Crime rates in poor black areas vs poor white areas .......?

Why do so many poor black areas such as in Detroit, Chicago and NYC have such high violent crime rates whereas many equally poor or poorer poor white areas such as in Appalachia or the Ozarks have much lower violent crime rates ?
Update: The 4 most dangerous cities in America per violent crimes are

1 St Louis
2 Detroit
4 Compton .....which are all poor black areas .....not poor white areas
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