President Donald Trump's decision came shortly after a top North Korean diplomat insulted the vice president, but there may be more at play.
North Korea said it would it would take apart its only known nuclear test site, and these images show its already started.
New satellite imagery shows a significant slowdown in activity at North Korea's Punggye-ri nuclear test site, just as Kim Jong Un reached out to Trump.
Seoul's unification ministry conducted check-ups on 30 North Koreans who left before January 2016.
News of Park's alleged execution follows reports that North Korea's second most powerful official after leader Kim Jong Un has been punished.
The South and North Development (SAND) research institute reported the situation in a village near the Punggye-ri nuclear facility.
The Punngye-ri underground facility hosted the country's sixth and most powerful nuclear test to date.
South Korean and Chinese scientists worry that a collapse at the mountain could trigger a radiation leak.
The nuclear test has made the mountainous location unsuitable as a base.