A Passaic County man has been charged after allegedly sending sexually explicit material to an undercover detective on social media, the Monmouth County Prosecutor’s Office announced Friday. Joseph Velazquez, 25, of Passaic, is charged with second- and third-degree endangering the welfare of a child for allegedly possessing and distributing child pornography, authorities said. In February, authorities opened an investigation into Velazquez after a detective monitoring a group chat on the social media app Kik, was contacted by him under the alias blazeitupp1, the prosecutor’s office said. Velaz…