In the thermal image (also from the 22nd July), thermal anomalies were also present inside the summit and secondary craters.
I would personally call this case inconclusive.
|Image from the 21st July 2014 showed a possible dark patch on the northeast side of Saunders Island. SOURCE: NASA.|
|In a better resolution image a slightly darkened patch shows up on the northeast side of the island. SOURCE: Landsat 8/USGS/NASA.|
|Thermal anomalies show up in the two craters of Mount Michael in this thermal image. SOURCE: Landsat 8/USGS/NASA.|