Lower level fear is defined by the Alter Rebbe in the introduction to Tikkun Chatzos in his siddur as follows:

Yira chitzonis is a result of being afraid as one would be in the presence of a physical king, who, because of the extent of his sovereignty, inspires fear. As a result of his malchus, sovereignty, on fears, i.e., it is primitive, perhaps immature.

The same applies to G-d. The lower fear would be as a result of thinking about how great G-d’s creation (malchus) is and how everything is under His control. One would be motivated to yiras onesh (fear of punishment) or yiras cheit (fear of the sin itself).