Twice.
And the Trumpet will be blown, and all who are in the heavens and all who are on the earth will swoon away, except him whom Allah will. Then it will blown a second time and behold, they will be standing, looking on (waiting).Az-zummar 39:68
سينفخ مرتين في الصور
( وَنُفِخَ فِي الصُّورِ فَصَعِقَ مَن فِي السَّمَاوَاتِ وَمَن فِي الْأَرْضِ إِلَّا مَن شَاءَ اللَّـهُ
ثُمَّ نُفِخَ فِيهِ أُخْرَىٰ فَإِذَا هُمْ قِيَامٌ يَنظُرُونَ الزمر 39: 68