Network hashrate is from 3 to 12 MH. Hashrate of all mining pools is about 400 KH. The rest is ASIC mining in solo?
Dev, it is necessary to block ASIC mining. If is posssible.
Check the explorer
https://explorer.pluracoin.org/, these are short peaks not constant mining. It could possibly be Nicehash bought by some newbie. It simply doesn't make sense to put such high hashrate for a such short period of time.