ɪɴᴛᴇʀᴇsᴛɪɴɢ ᴄʟᴏᴜᴅ ᴀɴᴅ ᴀᴘᴏᴄᴀʟʏᴘᴛɪᴄ sᴏᴜɴᴅ sʟᴏᴠᴀᴋɪᴀ ᴍʏsᴛᴇʀɪᴏᴜsʟʏ sᴏᴜɴᴅs ᴀʀᴇ ʙᴀᴄᴋ. ɪs ɪᴛ ʀᴇʟᴀᴛᴇᴅ ᴛᴏs ᴇxᴄᴇssɪᴠᴇʟʏ ʜɪɢʜ ɢʟᴏʙᴀʟ sᴇɪsᴍɪᴄ ᴀᴄᴛɪᴠɪᴛʏ?
With frequent observations of these sounds, I noticed that this mysterious sound can be heard before or after the bigger...