aws ec2 describe-instances --filters "Name=tag:Name,Values=UST1TWASDEVP02A" --query "Reservations[*].Instances[*].BlockDeviceMappings[*].Ebs.[VolumeId]"

[
    [
        [
            [
                "vol-0eb27ed4482aa6b72"
            ],
            [
                "vol-0a8a5716d4abb92cc"
            ],
            [
                "vol-0adb47a85b3541697"
            ]
        ]
    ]
]

aws ec2 describe-instances --filters Name=tag:Name,Values=UST1TWASDEVP02A" | jq -r .Reservations[0].Instances[0].BlockDeviceMappings[1].Ebs.VolumeId