EXHIBIT 21.1

Name of Subsidiary	Other Name Under Which Subsidiary Conducts Business	Jurisdiction Of Incorporation
Quantum Geophysical Services, Inc. (formerly Quantum Geophysical, Inc.)	None	Texas
Quantum Geophysical, Inc.	None	Texas
Geophysical Development Corporation	None	Texas
Trace Energy Services Ltd.	None	Alberta, Canada

Following is a list of the subsidiaries of Geophysical Development Corporation:

Name of Subsidiary	Other Name Under Which Subsidiary Conducts Business	Jurisdiction Of Incorporation
GDC UK Limited	None	England

Following is a list of the subsidiaries of Trace Energy Services Ltd.:

Name of Subsidiary	Other Name Under Which Subsidiary Conducts Business	Jurisdiction Of Incorporation
Trace Energy Services, Inc.	None	Texas