FIFTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT

EXHIBIT 10.1

FIFTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT

     This Fifth Amendment to Amended and Restated Credit Agreement (the “ Fifth Amendment ” or “this Amendment ”) is made and entered into effective as of the 1st day of June, 2009 (the “ Fifth Amendment Effective Date ”), by and among ION GEOPHYSICAL CORPORATION, a Delaware corporation (the “ Domestic Borrower ”), ION INTERNATIONAL S.À R.L., a Luxembourg private limited company ( société à responsabilité limitée ), having its registered office at 65, Boulevard Grande — Duchesse Charlotte, L-1331 Luxembourg, with a share capital of EUR12,500, and registered with the Luxembourg Register of Commerce and Companies under the number B-135.679 (the “ Foreign Borrower ” and together with the Domestic Borrower, the “ Borrowers ”), the Guarantors party hereto (the “ Guarantors ”), the Lenders party hereto, and HSBC BANK USA, N.A., as administrative agent (the “ Administrative Agent ”).

RECITALS

     WHEREAS, the above-named parties have entered into that certain Amended and Restated Credit Agreement dated as of July 3, 2008, as amended by that certain First Amendment to Amended and Restated Credit Agreement and Domestic Security Agreement dated as of September 17, 2008, that certain Second Amendment to Amended and Restated Credit Agreement dated as of October 17, 2008, that certain Third Amendment to Amended and Restated Credit Agreement dated as of December 29, 2008, and that certain Fourth Amendment to Amended and Restated Credit Agreement and Foreign Security Agreement, Limited Waiver and Release dated as of December 30, 2008 (and as may be further amended, restated, modified or supplemented from time to time, the “ Credit Agreement ”), by and among the Borrowers, the Guarantors, the Lenders and the Administrative Agent; and

     WHEREAS, the Borrowers have requested that the Lenders and the Administrative Agent amend certain provisions to the Credit Agreement, and said parties are willing to do so subject to the terms and conditions set forth herein, provided that the Domestic Borrower and Domestic Guarantors ratify and confirm all of their respective obligations under the Credit Agreement and each other Loan Document to which each is a party and that the Foreign Borrower and Foreign Guarantors ratify and confirm all of their respective obligations under the Credit Agreement and each other Loan Document to which each is a party.

     NOW, THEREFORE, in consideration of the foregoing and the mutual covenants set forth in this Amendment, Borrowers, Guarantors, the Lenders party hereto and the Administrative Agent agree as follows:

     1.  Defined Terms . Unless otherwise defined herein, capitalized terms used herein have the meanings assigned to them in the Credit Agreement.

     2.  Amendments . (a) The Credit Agreement is hereby amended as follows:

     (i) Amendments to Section 1.01 . Section 1.01 is hereby amended by deleting the following definitions and restating them in their entirety to read as follows:

     “ Applicable Margin ” means, on any day, for any Revolving Loan, the applicable per annum percentage set forth at the appropriate intersection in the Revolving Loans table shown below, and, for the Term Loans, the applicable per annum percentage set forth at the appropriate intersection in the Term Loans table shown below, each of which is based on the Leverage Ratio for the most recently ended trailing four-quarter period with respect to which the Domestic Borrower is required to have delivered the financial statements and Compliance Certificate pursuant to Section 5.01 hereof (as such Leverage Ratio is reflected in the Compliance Certificate delivered under Section 5.01(b) by the Domestic Borrower in connection with such financial statements):

           Revolving Loans

           Term Loans

Each change in the Applicable Margin shall take effect on each date on which such financial statements and Compliance Certificate are required to be delivered pursuant to Section 5.01 , commencing with the date on which such financial statements and Compliance Certificate are required to be delivered for the four-quarter period ending June 30, 2008. Notwithstanding the foregoing, for the two (2) quarterly periods following the date of the First Amendment Effective Date, the Applicable Margin shall be determined at Level IV. In the event that any financial statement delivered pursuant to Section 5.01 is shown to be inaccurate

when delivered (regardless of whether this Agreement or the Revolving Loan Commitments are in effect when such inaccuracy is discovered), and such inaccuracy, if corrected, would have led to the application of a higher Applicable Margin for any period (an “Applicable Period”) than the Applicable Margin applied for such Applicable Period, and only in such case, then the Domestic Borrower shall immediately (i) deliver to the Administrative Agent corrected financial statements for such Applicable Period, (ii) determine the Applicable Margin for such Applicable Period based upon the corrected financial statements, and (iii) immediately pay to the Administrative Agent the accrued additional interest owing as a result of such increased Applicable Margin for such Applicable Period, which payment shall be promptly applied by the Administrative Agent in accordance with Section 2.16(a) . This provision is in addition to the rights of the Administrative Agent and the Lenders with respect to Section 2.11(d) and their other respective rights under this Agreement. If the Domestic Borrower fails to deliver the financial statements and corresponding Compliance Certificate to the Administrative Agent at the time required pursuant to Section 5.01 , then effective as of the date such financial statements and corresponding Compliance Certificate were required to the delivered pursuant to Section 5.01 , the Applicable Margin shall be determined at Level IV and shall remain at such level until the date such financial statements and corresponding Compliance Certificate are so delivered by the Domestic Borrower. The Applicable Margin for the Term Loans shall be increased by 0.25% at all levels, and the Applicable Margin for the Revolving Loans shall be increased by 0.50% at all levels, in each case, commencing on the First Amendment Effective Date and ending on the date the Domestic Borrower repays the Revolving Loans borrowed for the purpose of financing the ARAM Acquisition.

  “ Commitment Fee Rate ” means, on any day, the applicable per annum percentage set forth at the appropriate intersection in the table shown below, based on the Leverage Ratio for the most recently ended trailing four-quarter period with respect to which the Domestic Borrower is required to have delivered the financial statements pursuant to Section 5.01 hereof (as such Leverage Ratio is reflected in the Compliance Certificate delivered under Section 5.01(b) by the Domestic Borrower in connection with such financial statements):

Each change in the Commitment Fee Rate shall take effect on each date on which such financial statements and Compliance Certificate are required to be delivered pursuant to Section 5.01 , commencing with the date on which such financials statements and Compliance Certificate are required to be delivered for the four-quarter period ending June 30, 2008. Notwithstanding the foregoing, for the period from the Effective Date through the date the financial statements and Compliance Certificate are required to be delivered pursuant to Section 5.01 for the fiscal quarter ended June 30, 2008, the Commitment Fee Rate shall be determined at Level I. In the event any financial statement delivered pursuant to Section 5.01 is shown to be inaccurate when delivered (regardless of whether this Agreement or the Revolving Loan Commitments are in effect when such inaccuracy is discovered), and such inaccuracy, if corrected, would have led to a higher Commitment Fee Rate for any period (an “ Applicable Commitment Fee Period ”) than the Commitment Fee Rate applied for such Applicable Commitment Fee Period, and only in such case, then the Domestic Borrower shall immediately (i) deliver to the Administrative Agent corrected financial statements for such Applicable Commitment Fee Period, (ii) determine the Commitment Fee Rate for such Applicable Commitment Fee Period based on the corrected financial statements, and (iii) immediately pay to the Administrative Agent the additional accrued commitment fees owing as a result of such increased Commitment Fee Rate for such Applicable Commitment Fee Period, which payment shall be promptly applied in accordance with Section 2.16(a) . This provision is in addition to the rights of the Administrative Agents and Lenders with respect to Section 2.11(d) and their other respective rights under this Agreement. If the Domestic Borrower fails to deliver the financial statements and corresponding Compliance Certificate to the Administrative Agent at the time required pursuant to Section 5.01 , then effective as of the date such financial statements and corresponding Compliance Certificate were required to the delivered pursuant to Section 5.01 , the Commitment Fee Rate shall be determined at Level IV and shall remain at such level until the date such financial statements and corresponding Compliance Certificate are so delivered by the Domestic Borrower.”

     “ Consolidated EBITDA ” means, for any period and for any Person, Consolidated Net Income of such Person for such period plus, to the extent deducted in determining Consolidated Net Income for such period, the aggregate of (i) Consolidated Interest Expense, (ii) income tax expense and (iii) depreciation, amortization and other similar non-cash charges; provided that, any add-back pursuant to subparagraph (iii) above in respect of any write downs in the value of inventory shall be limited to $5,000,000 for each of the fiscal quarters ending June 30, 2009, September 30, 2009 and December 31, 2009, and thereafter for any subsequent fiscal quarter for which either (x) the Leverage Ratio of the Domestic Borrower and its Subsidiaries would otherwise be equal to or greater than 2.25 to 1.0 or (y) the Fixed Charge Coverage Ratio of the Domestic Borrower and its Subsidiaries would otherwise be equal to or less than 1.50 to 1.0, in each case, without giving effect to such add-back. The Consolidated EBITDA of any Person acquired subsequent to the Effective Date shall be, as of the date of acquisition, without duplication, said Person’s

Consolidated EBITDA calculated for the most recently completed twelve month period ended prior to such acquisition and, thereafter, its Consolidated EBITDA calculated on a rolling four quarter basis.

     (b) Section 1.01 is hereby further amended by adding the following definition thereto in the proper alphabetical order.

     “ Call-Spread Transaction ” means that certain proposed capped call transaction to be entered into by the Domestic Borrower on or before June 30, 2009, pursuant to which the Domestic Borrower purchases from a third-party one or more options to purchase its common Equity Interests, on terms reasonably satisfactory to the Administrative Agent.

     “ Excess Cash Flow ” means for any period of four consecutive quarters ending on December 31 of any year, the excess of Consolidated EBITDA for such period minus, without duplication, the sum of (i) cash taxes actually paid, (ii) cash interest actually paid, (iii) non-financed Consolidated Capital Expenditures, (iv) actual principal payments made in respect of long term Indebtedness, (v) actual principal payments made in respect of Consolidated Capital Lease Obligations, (vi) transaction costs, and (vii) dividends actually paid (to the extent permitted hereunder) in respect of its Consolidated Preferred Stock.”

     “ Fifth Amendment Effective Date ” means June ___, 2009.

     “ ICON Capital ” means ICON Capital Corp., a Delaware corporation.

     “ ICON Capital Financing ” means an equipment financing facility in the original principal amount not exceeding $20,000,000 and having a maturity date of not less than five (5) years, entered into between or among the New ION Equipment Financing Subsidiaries and ICON Capital, pursuant to which the New ION Equipment Financing Subsidiaries shall finance or refinance equipment, primarily located in Canada, on terms reasonably satisfactory to the Administrative Agent.”

     “ New ION Equipment Financing Subsidiaries ” means collectively, the New ION US Equipment Financing Subsidiary and New ION CN Equipment Financing Subsidiary.

     “ New ION US Equipment Financing Subsidiary ” means a direct or indirect wholly-owned Subsidiary to be formed pursuant to the ICON Capital Financing as a “special purpose entity” to own and operate the equipment located in the US.

     “ New ION CN Equipment Financing Subsidiary ” means a direct or indirect wholly-owned Subsidiary to be formed pursuant to the ICON Capital Financing as a “special purpose entity” to own and operate the equipment located in Canada.

     (c) Section 1.01 is hereby further amended by amending and restating paragraph (w) and adding paragraph (aa) of the definition of Permitted Liens, each to read as follows:

     “(w) Liens to secure Capital Lease Obligations permitted under Section 6.01(g) ; provided that such Liens attach only to the Property that is the subject of such Capital Lease Obligation;”

     “(aa) Liens securing the ICON Capital Financing, including Liens on the equipment of any New ION Equipment Financing Subsidiary financed (or refinanced) thereunder, rental or leasing contracts with respect to such equipment, rental payments, lease payments and other proceeds thereof, bank accounts into which such payments or proceeds are delivered and any and all other personal property and rights of any New ION Equipment Financing Subsidiary appert