EXHIBIT 4.9

FOURTH SUPPLEMENTAL INDENTURE

Fourth Supplemental Indenture (this “Supplemental Indenture”), dated as of March 16, 2012, among STRM, LLC, a Colorado limited liability company (the “Guaranteeing Subsidiary”), an indirect subsidiary of Global Geophysical Services, Inc. (or its permitted successor), a Delaware corporation (the “Company”), the Company, the other Guarantors (as defined in the Indenture referred to below) and The Bank of New York Mellon Trust Company, N.A., as trustee under the Indenture referred to below (the “Trustee”).

W I T N E S S E T H

WHEREAS, the Company has heretofore executed and delivered to the Trustee an indenture (as supplemented and amended by the First Supplemental Indenture dated as of September 10, 2010, the Second Supplemental Indenture dated as of November 10, 2010 and the Third Supplemental Indenture dated as of December 9, 2010, the “Indenture”), dated as of April 27, 2010 providing for the issuance of 10½% Senior Notes due 2017 (the “Notes”);

WHEREAS, the Indenture provides that under certain circumstances each guaranteeing subsidiary under the Indenture shall execute and deliver to the Trustee a supplemental indenture pursuant to which the Guaranteeing Subsidiary shall unconditionally guarantee all of the Company's Obligations under the Notes and the Indenture on the terms and conditions set forth herein (the “Subsidiary Guarantee”); and

WHEREAS, pursuant to Section 9.01 of the Indenture, the Trustee is authorized to execute and deliver this Fourth Supplemental Indenture.

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Guaranteeing Subsidiary and the Trustee mutually covenant and agree for the equal and ratable benefit of the Holders of the Notes as follows:

1.           Capitalized terms. Capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

2.           Agreement to Guarantee.  The Guaranteeing Subsidiary hereby agrees to provide an unconditional Guarantee on the terms and subject to the conditions set forth in the Subsidiary Guarantee and in the Indenture including but not limited to Article 10 thereof.

3.           No Recourse Against Others. No director, officer, employee, manager, incorporator, member, partner or stockholder or other owner of Capital Stock of the Company or any of its Subsidiaries, as such, shall have any liability for any obligations of the Company or any Guarantor under the Notes, the Subsidiary Guarantees or the Indenture or for any claim based on, in respect of, or by reason of, such obligations or their creation. Each Holder of a Note by accepting the Note waives and releases all such liability. The waiver and release are part of the consideration for issuance of the Notes. Such waiver may not be effective to waive liabilities

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under the federal securities laws, and it is the view of the SEC that such a waiver is against public policy.

4.           NEW YORK LAW TO GOVERN.  THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

5.           Counterparts. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement.

6.           Effect of Headings.  The Section headings herein are for convenience only and shall not affect the construction hereof.

7.           The Trustee.  The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Guaranteeing Subsidiary, the other Guarantors and the Company.

Signatures on the following page

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IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed and attested, all as of the date first above written.

STRM, LLC

as the Guaranteeing Subsidiary

AUTOSEIS DEVELOPMENT COMPANY

and

PAISANO LEASE CO., INC.

and

GLOBAL EURASIA, LLC

and

GLOBAL MICROSEISMIC SERVICES, INC.

and

GGS INTERNATIONAL HOLDINGS, INC.

and

AUTOSEIS, INC.

as the other Guarantors

GLOBAL GEOPHYSICAL SERVICES, INC.

as Company

All of the above by:

/s/ P. Mathew Verghese

Name:    P. Mathew Verghese

Title:      Senior Vice President and

Chief Financial Officer

[Signature Page of Trustee Follows]

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IN WITNESS WHEREOF, the Trustee has caused this Supplemental Indenture to be duly executed and attested, all as of the date first above written.

The Bank of New York Mellon Trust Company, N.A., as Trustee

By:           /s/ Julie Hoffman-Ramos

Authorized Signatory

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