続き
e2fsckを実行したところ以下のメッセージが得られました

sudo e2fsck -C0 -p -f -v /dev/sdb1
e2fsck: The ext2 superblock is corrupt while trying to open /dev/sdb1
/dev/sdb1:
The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem. If the device is valid and it really contains an ext2/ext3/ext4
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>
or
e2fsck -b 32768 <device>