|        |
|--------|
|        |  |  |
|   | þ | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 |

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|--------|
|        |  |  |
|   |  ̈ | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 |

|                                                                |
|----------------------------------------------------------------|
|                                                                |  |  |
| Delaware                                                       |   | 22-2286646 |
| (State or Other Jurisdiction of Incorporation or Organization) |   | (I.R.S. Employer Identification No.) |

|                               |
|-------------------------------|
|                               |  |  |
| Title of Each Class           |   | Name of Each Exchange on Which Registered |
| Common Stock, $0.01 par value |   | New York Stock Exchange |

|                                            |
|--------------------------------------------|
|                                            |  |  |  |  |  |  |
| Large accelerated filer    ̈ |   | Accelerated filer   þ |   | Non-accelerated filer    ̈ |   | Smaller reporting company   ̈ |

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|         |                                                                                                                                  |
|---------|----------------------------------------------------------------------------------------------------------------------------------|
| • | 3.2 Certificate of Amendment to the Restated Certificate of Incorporation of ION Geophysical Corporation dated February 2, 2016. |

|         |                                                                                                                                  |
|---------|----------------------------------------------------------------------------------------------------------------------------------|
| • | 3.3 Certificate of Amendment to the Restated Certificate of Incorporation of ION Geophysical Corporation dated February 4, 2016. |

|         |                                                           |
|---------|-----------------------------------------------------------|
| • | 10.39 Amended and Restated 2013 Long-Term Incentive Plan. |

|         |                                     |
|---------|-------------------------------------|
| • | 23.1 Consent of Grant Thornton LLP. |

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|        |
|--------|
|        |  |  |  |
| 3.1    | — | Restated Certificate of Incorporation dated September 24, 2007 filed on September 24, 2007 as Exhibit 3.4 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| *3.2   | — | Certificate of Amendment to the Restated Certificate of Incorporation of ION Geophysical Corporation dated February 2, 2016. |
| *3.3   | — | Certificate of Amendment to the Restated Certificate of Incorporation of ION Geophysical Corporation dated February 4, 2016. |
| 3.4    | — | Amended and Restated Bylaws of ION Geophysical Corporation filed on September 24, 2007 as Exhibit 3.5 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 3.5    | — | Certificate of Ownership and Merger merging ION Geophysical Corporation with and into Input/Output, Inc. dated September 21, 2007, filed on September 24, 2007 as Exhibit 3.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.1    | — | Certificate of Rights and Designations of Series D-1 Cumulative Convertible Preferred Stock, dated February 16, 2005 and filed on February 17, 2005 as Exhibit 3.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.2    | — | Certificate of Elimination of Series B Preferred Stock dated September 24, 2007, filed on September 24, 2007 as Exhibit 3.2 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.3    | — | Certificate of Elimination of Series C Preferred Stock dated September 24, 2007, filed on September 24, 2007 as Exhibit 3.3 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.4    | — | Certificate of Designation of Series D-2 Cumulative Convertible Preferred Stock dated December 6, 2007, filed on December 6, 2007 as Exhibit 3.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.5    | — | Certificate of Designations of Series A Junior Participating Preferred Stock of ION Geophysical Corporation effective as of December 31, 2008, filed on January 5, 2009 as Exhibit 3.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.6    | — | Certificate of Elimination of Series A Junior Participating Preferred Stock dated February 10, 2012, filed on February 13, 2012 as Exhibit 3.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 4.7    | — | Indenture, dated May 13, 2013, among ION Geophysical Corporation, the subsidiary guarantors named therein, Wilmington Trust, National Association, as trustee, and U.S. Bank National Association, as collateral agent, filed on May 13, 2013 as Exhibit 4.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.8    | — | Registration Rights Agreement, dated May 13, 2013, among ION Geophysical Corporation, the subsidiary guarantors named therein and Citigroup Global Markets Inc. and Wells Fargo Securities, LLC, as representatives of the initial purchasers named therein, filed on May 13, 2013 as Exhibit 4.2 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.9    | — | Certificate of Elimination of Series D-1 Cumulative Convertible Preferred Stock dated September 30, 2013, filed on September 30, 2013 as Exhibit 3.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.10   | — | Certificate of Elimination of Series D-2 Cumulative Convertible Preferred Stock dated September 30, 2013, filed on September 30, 2013 as Exhibit 3.2 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| **10.1 | — | Amended and Restated 1990 Stock Option Plan, filed on June 9, 1999 as Exhibit 4.2 to the Company’s Registration Statement on Form S-8 (Registration No. 333-80299), and incorporated herein by reference. |
| 10.2   | — | Office and Industrial/Commercial Lease dated June 2005 by and between Stafford Office Park II, LP as Landlord and Input/Output, Inc. as Tenant, filed on March 31, 2006 as Exhibit 10.2 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2005, and incorporated herein by reference. |
| 10.3   | — | Office and Industrial/Commercial Lease dated June 2005 by and between Stafford Office Park District as Landlord and Input/Output, Inc. as Tenant, filed on March 31, 2006 as Exhibit 10.3 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2005, and incorporated herein by reference. |

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|         |
|---------|
|         |  |  |  |
| **10.4  | — | Input/Output, Inc. Amended and Restated 1996 Non-Employee Director Stock Option Plan, filed on June 9, 1999 as Exhibit 4.3 to the Company’s Registration Statement on Form S-8 (Registration No. 333-80299), and incorporated herein by reference. |
| **10.5  | — | Amendment No. 1 to the Input/Output, Inc. Amended and Restated 1996 Non-Employee Director Stock Option Plan dated September 13, 1999 filed on November 14, 1999 as Exhibit 10.4 to the Company’s Quarterly Report on Form 10-Q for the fiscal quarter ended August 31, 1999 and incorporated herein by reference. |
| **10.6  | — | Input/Output, Inc. Employee Stock Purchase Plan, filed on March 28, 1997 as Exhibit 4.4 to the Company’s Registration Statement on Form S-8 (Registration No. 333-24125), and incorporated herein by reference. |
| **10.7  | — | Fifth Amended and Restated - 2004 Long-Term Incentive Plan, filed as Appendix A to the definitive proxy statement for the 2010 Annual Meeting of Stockholders of ION Geophysical Corporation, filed on April 21, 2010, and incorporated herein by reference. |
| 10.8    | — | Registration Rights Agreement dated as of November 16, 1998, by and among the Company and The Laitram Corporation, filed on March 12, 2004 as Exhibit 10.7 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2003, and incorporated herein by reference. |
| **10.9  | — | Input/Output, Inc. 1998 Restricted Stock Plan dated as of June 1, 1998, filed on June 9, 1999 as Exhibit 4.7 to the Company’s Registration Statement on S-8 (Registration No. 333-80297), and incorporated herein by reference. |
| **10.10 | — | Input/Output Inc. Non-qualified Deferred Compensation Plan, filed on April 1, 2002 as Exhibit 10.14 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2001, and incorporated herein by reference. |
| **10.11 | — | Input/Output, Inc. 2000 Restricted Stock Plan, effective as of March 13, 2000, filed on August 17, 2000 as Exhibit 10.27 to the Company’s Annual Report on Form 10-K for the fiscal year ended May 31, 2000, and incorporated herein by reference. |
| **10.12 | — | Input/Output, Inc. 2000 Long-Term Incentive Plan, filed on November 6, 2000 as Exhibit 4.7 to the Company’s Registration Statement on Form S-8 (Registration No. 333-49382), and incorporated by reference herein. |
| **10.13 | — | Employment Agreement dated effective as of March 31, 2003, by and between the Company and Robert P. Peebler, filed on March 31, 2003 as Exhibit 10.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| **10.14 | — | First Amendment to Employment Agreement dated September 6, 2006, between Input/Output, Inc. and Robert P. Peebler, filed on September 7, 2006, as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.15 | — | Second Amendment to Employment Agreement dated February 16, 2007, between Input/Output, Inc. and Robert P. Peebler, filed on February 16, 2007 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.16 | — | Third Amendment to Employment Agreement dated as of August 20, 2007 between Input/Output, Inc. and Robert P. Peebler, filed on August 21, 2007 as Exhibit 10.2 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| **10.17 | — | Fourth Amendment to Employment Agreement, dated as of January 26, 2009, between ION Geophysical Corporation and Robert P. Peebler, filed on January 29, 2009 as Exhibit 10.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| **10.18 | — | Employment Agreement dated effective as of June 15, 2004, by and between the Company and David L. Roland, filed on August 9, 2004 as Exhibit 10.5 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2004, and incorporated herein by reference. |
| **10.19 | — | GX Technology Corporation Employee Stock Option Plan, filed on August 9, 2004 as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2004, and incorporated herein by reference. |
| 10.20   | — | Concept Systems Holdings Limited Share Acquisition Agreement dated February 23, 2004, filed on March 5, 2004 as Exhibit 2.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 10.21   | — | Registration Rights Agreement by and between ION Geophysical Corporation and 1236929 Alberta Ltd. dated September 18, 2008, filed on November 7, 2008 as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q and incorporated herein by reference. |
| **10.22 | — | Form of Employment Inducement Stock Option Agreement for the Input/Output, Inc. - Concept Systems Employment Inducement Stock Option Program, filed on July 27, 2004 as Exhibit 4.1 to the Company’s Registration Statement on Form S-8 (Reg. No. 333-117716), and incorporated herein by reference. |

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|         |
|---------|
|         |  |  |  |
| **10.23 | — | Form of Employee Stock Option Award Agreement for ARAM Systems Employee Inducement Stock Option Program, filed on November 14, 2008 as Exhibit 4.4 to the Company’s Registration Statement on Form S-8 (Registration No. 333-155378) and incorporated herein by reference. |
| **10.24 | — | Input/Output, Inc. 2003 Stock Option Plan, dated March 27, 2003, filed as Appendix B of the Company’s definitive proxy statement filed with the SEC on April 30, 2003, and incorporated herein by reference. |
| **10.25 | — | Form of Employment Inducement Stock Option Agreement for the Input/Output, Inc. - GX Technology Corporation Employment Inducement Stock Option Program, filed on April 4, 2005 as Exhibit 4.1 to the Company’s Registration Statement on Form S-8 (Reg. No. 333-123831), and incorporated herein by reference. |
| **10.26 | — | ION Stock Appreciation Rights Plan dated November 17, 2008, filed as Exhibit 10.47 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2008, and incorporated herein by reference. |
| 10.27   | — | Canadian Master Loan and Security Agreement dated as of June 29, 2009 by and among ICON ION, LLC, as lender, ION Geophysical Corporation and ARAM Rentals Corporation, a Nova Scotia corporation, filed on August 6, 2009 as Exhibit 10.3 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2009, and incorporated herein by reference. |
| 10.28   | — | Master Loan and Security Agreement (U.S.) dated as of June 29, 2009 by and among ICON ION, LLC, as lender, ION Geophysical Corporation and ARAM Seismic Rentals, Inc., a Texas corporation, filed on August 6, 2009 as Exhibit 10.4 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2009, and incorporated herein by reference. |
| 10.29   | — | Registration Rights Agreement dated as of October 23, 2009 by and between ION Geophysical Corporation and BGP Inc., China National Petroleum Corporation filed on March 1, 2010 as Exhibit 10.54 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2009, and incorporated herein by reference. |
| 10.30   | — | Stock Purchase Agreement dated as of March 19, 2010, by and between ION Geophysical Corporation and BGP Inc., China National Petroleum Corporation, filed on March 31, 2010 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 10.31   | — | Investor Rights Agreement dated as of March 25, 2010, by and between ION Geophysical Corporation and BGP Inc., China National Petroleum Corporation, filed on March 31, 2010 as Exhibit 10.2 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 10.32   | — | Share Purchase Agreement dated as of March 24, 2010, by and among ION Geophysical Corporation, INOVA Geophysical Equipment Limited and BGP Inc., China National Petroleum Corporation, filed on March 31, 2010 as Exhibit 10.3 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 10.33   | — | Joint Venture Agreement dated as of March 24, 2010, by and between ION Geophysical Corporation and BGP Inc., China National Petroleum Corporation, filed on March 31, 2010 as Exhibit 10.4 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.34 | — | Fifth Amendment to Employment Agreement dated June 1, 2010, between ION Geophysical Corporation and Robert P. Peebler, filed on June 1, 2010 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.35 | — | Employment Agreement dated August 2, 2011, effective as of January 1, 2012, between ION Geophysical Corporation and R. Brian Hanson, filed on November 3, 2011 as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2011, and incorporated herein by reference. |
| **10.36 | — | Employment Agreement dated effective as of November 28, 2011, between ION Geophysical Corporation and Gregory J. Heinlein, filed on December 1, 2011 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.37 | — | First Amendment to Credit Agreement and Loan Documents dated May 29, 2012, filed on May 29, 2012 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.38 | — | Consulting Services Agreement dated January 1, 2013, between ION Geophysical Corporation and ThePeebler Group LLC, filed on January 4, 2013 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| *10.39  | — | Amended and Restated 2013 Long-Term Incentive Plan. |
| 10.40   | — | Purchase Agreement, dated May 8, 2013, among ION Geophysical Corporation, the subsidiary guarantors named therein and Citigroup Global Markets Inc. and Wells Fargo Securities, LLC, as representatives of the initial purchasers named therein, filed on May 13, 2013 as Exhibit 10.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference |

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|                                                            |
|------------------------------------------------------------|
|                                                            |  |  |  |
| 10.41                                                      | — | Second Lien Intercreditor Agreement by and among China Merchants Bank Co., Ltd., New York Branch, as administrative agent, first lien representative for the first lien secured parties and collateral agent for the first lien secured parties, Wilmington Trust Company, National Association, as trustee and second lien representative for the second lien secured parties, and U.S. Bank National Association, as collateral agent for the second lien secured parties, and acknowledged and agreed to by ION Geophysical Corporation and the other grantors named therein, filed on May 13, 2013 as Exhibit 10.2 to the Company’s Current Report on Form 8-K and incorporated herein by reference |
| 10.42                                                      | — | Revolving Credit and Security Agreement dated as of August 22, 2014 among PNC Bank, National Association, as agent for lenders, the lenders from time to time party thereto, as lenders, and PNC Capital Markets LLC, as lead arranger and bookrunner, with ION Geophysical Corporation, ION Exploration Products (U.S.A.), Inc., I/O Marine Systems, Inc. and GX Technology Corporation, as borrowers, filed on November 6, 2014 as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2014, and incorporated herein by reference. |
| **10.43                                                    | — | Transition and Separation Agreement dated effective as of October 30, 2014, by and between ION Geophysical Corporation and Gregory J. Heinlein. |
| **10.44                                                    | — | Employment Agreement dated effective as of November 13, 2014, between ION Geophysical Corporation and Steve Bate. |
| **10.45                                                    | — | Form of Rights Agreement dated March 1, 2015 issued under the ION Stock Appreciation Rights Plan dated November 17, 2008, filed on May 7, 2015 as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2015, and incorporated herein by reference. |
| 10.46                                                      | — | First Amendment to Revolving Credit and Security Agreement dated as of August 4, 2015 among PNC Bank, National Association, as lender and agent, the lenders from time to time party thereto, as lenders, with ION Geophysical Corporation, ION Exploration Products (U.S.A.), Inc., I/O Marine Systems, Inc. and GX Technology Corporation, as borrowers, filed on August 6, 2015 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 21.1                                                       | — | Subsidiaries of the Company. |
| *23.1                                                      | — | Consent of Grant Thornton LLP. |
| 23.2                                                       | — | Consent of Ernst & Young LLP. |
| 24.1                                                       | — | The Power of Attorney is set forth on the signature page hereof. |
| 25.1                                                       | — | Registration Statement (Form S-4 No. 333-194110) of ION Geophysical Corporation, and incorporated herein by reference. |
| *31.1                                                      | — | Certification of Chief Executive Officer Pursuant to Rule 13a-14(a) or Rule 15d-14(a). |
| *31.2                                                      | — | Certification of Chief Financial Officer Pursuant to Rule 13a-14(a) or Rule 15d-14(a). |
| *32.1                                                      | — | Certification of Chief Executive Officer Pursuant to 18 U.S.C. §1350. |
| *32.2                                                      | — | Certification of Chief Financial Officer Pursuant to 18 U.S.C. §1350. |
| 101                                                        | — | The following materials are formatted in Extensible Business Reporting Language (XBRL): (i) Consolidated Balance Sheets at December 31, 2015 and 2014, (ii) Consolidated Statements of Operations for the years ended December 31, 2015, 2014 and 2013, (iii) Comprehensive Income (Loss) for the years ended December 31, 2015, 2014 and 2013, (iv) Consolidated Statements of Cash Flows for the years ended December 31, 2015, 2014 and 2013, (v) Consolidated Statements of Stockholders’ Equity for the years ended December 31, 2015, 2014 and 2013, (vi) Footnotes to Consolidated Financial Statements and (vii) Schedule II - Valuation and Qualifying Accounts. |
|                                                       |   |   |
|    *Filed herewith.                         |
| **Management contract or compensatory plan or arrangement. |

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|        |
|--------|
|        |  |  |  |
|   | ION GEOPHYSICAL CORPORATION |
|   |   |   |
|   | By |   | /s/ R. Brian Hanson |
|   |   |   | R. Brian Hanson |
|   |   |   | President and Chief Executive Officer |

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|                       |
|-----------------------|
|                       |  |  |  |  |
| Name                  |   | Capacities |   | Date |
|                  |   |   |
| /s/ R. Brian Hanson   |   | President, Chief Executive Officer and Director(Principal Executive Officer) |   | February 12, 2016 |
| R. Brian Hanson       |   |   |   |
|                  |   |   |
| *                     |   | Executive Vice President and ChiefFinancial Officer (Principal Financial Officer) |   | February 12, 2016 |
| Steven A. Bate        |   |   |   |
|                  |   |   |
| *                     |   | Vice President and Corporate Controller(Principal Accounting Officer) |   | February 12, 2016 |
| Scott Schwausch       |   |   |   |
|                  |   |   |
| *                     |   | Chairman of the Board of Directors and Director |   | February 12, 2016 |
| James M. Lapeyre, Jr. |   |   |   |
|                  |   |   |
| *                     |   | Director |   | February 12, 2016 |
| David H. Barr         |   |   |   |
|                  |   |   |
| *                     |   | Director |   | February 12, 2016 |
| Hao Huimin            |   |   |   |

|                      |
|----------------------|
|                      |  |  |  |  |
|                 |   |   |   |   |
|                 |   |   |
| *                    |   | Director |   | February 12, 2016 |
| Michael C. Jennings  |   |   |   |
|                 |   |   |
| *                    |   | Director |   | February 12, 2016 |
| Franklin Myers       |   |   |   |
|                 |   |   |
| *                    |   | Director |   | February 12, 2016 |
| S. James Nelson, Jr. |   |   |   |
|                 |   |   |
| *                    |   | Director |   | February 12, 2016 |
| John N. Seitz        |   |   |   |

|        |
|--------|
|        |  |  |
| *By:   |   | /s/ R. Brian Hanson |
|   |   | R. Brian Hanson |
|   |   | Attorney-in-fact |

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|--------|
|        |  |  |  |
| 3.1    | — | Restated Certificate of Incorporation dated September 24, 2007 filed on September 24, 2007 as Exhibit 3.4 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| *3.2   | — | Certificate of Amendment to the Restated Certificate of Incorporation of ION Geophysical Corporation dated February 2, 2016. |
| *3.3   | — | Certificate of Amendment to the Restated Certificate of Incorporation of ION Geophysical Corporation dated February 4, 2016. |
| 3.4    | — | Amended and Restated Bylaws of ION Geophysical Corporation filed on September 24, 2007 as Exhibit 3.5 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 3.5    | — | Certificate of Ownership and Merger merging ION Geophysical Corporation with and into Input/Output, Inc. dated September 21, 2007, filed on September 24, 2007 as Exhibit 3.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.1    | — | Certificate of Rights and Designations of Series D-1 Cumulative Convertible Preferred Stock, dated February 16, 2005 and filed on February 17, 2005 as Exhibit 3.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.2    | — | Certificate of Elimination of Series B Preferred Stock dated September 24, 2007, filed on September 24, 2007 as Exhibit 3.2 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.3    | — | Certificate of Elimination of Series C Preferred Stock dated September 24, 2007, filed on September 24, 2007 as Exhibit 3.3 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.4    | — | Certificate of Designation of Series D-2 Cumulative Convertible Preferred Stock dated December 6, 2007, filed on December 6, 2007 as Exhibit 3.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.5    | — | Certificate of Designations of Series A Junior Participating Preferred Stock of ION Geophysical Corporation effective as of December 31, 2008, filed on January 5, 2009 as Exhibit 3.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.6    | — | Certificate of Elimination of Series A Junior Participating Preferred Stock dated February 10, 2012, filed on February 13, 2012 as Exhibit 3.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 4.7    | — | Indenture, dated May 13, 2013, among ION Geophysical Corporation, the subsidiary guarantors named therein, Wilmington Trust, National Association, as trustee, and U.S. Bank National Association, as collateral agent, filed on May 13, 2013 as Exhibit 4.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.8    | — | Registration Rights Agreement, dated May 13, 2013, among ION Geophysical Corporation, the subsidiary guarantors named therein and Citigroup Global Markets Inc. and Wells Fargo Securities, LLC, as representatives of the initial purchasers named therein, filed on May 13, 2013 as Exhibit 4.2 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.9    | — | Certificate of Elimination of Series D-1 Cumulative Convertible Preferred Stock dated September 30, 2013, filed on September 30, 2013 as Exhibit 3.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| 4.10   | — | Certificate of Elimination of Series D-2 Cumulative Convertible Preferred Stock dated September 30, 2013, filed on September 30, 2013 as Exhibit 3.2 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| **10.1 | — | Amended and Restated 1990 Stock Option Plan, filed on June 9, 1999 as Exhibit 4.2 to the Company’s Registration Statement on Form S-8 (Registration No. 333-80299), and incorporated herein by reference. |
| 10.2   | — | Office and Industrial/Commercial Lease dated June 2005 by and between Stafford Office Park II, LP as Landlord and Input/Output, Inc. as Tenant, filed on March 31, 2006 as Exhibit 10.2 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2005, and incorporated herein by reference. |
| 10.3   | — | Office and Industrial/Commercial Lease dated June 2005 by and between Stafford Office Park District as Landlord and Input/Output, Inc. as Tenant, filed on March 31, 2006 as Exhibit 10.3 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2005, and incorporated herein by reference. |
| **10.4 | — | Input/Output, Inc. Amended and Restated 1996 Non-Employee Director Stock Option Plan, filed on June 9, 1999 as Exhibit 4.3 to the Company’s Registration Statement on Form S-8 (Registration No. 333-80299), and incorporated herein by reference. |

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|         |
|---------|
|         |  |  |  |
| **10.5  | — | Amendment No. 1 to the Input/Output, Inc. Amended and Restated 1996 Non-Employee Director Stock Option Plan dated September 13, 1999 filed on November 14, 1999 as Exhibit 10.4 to the Company’s Quarterly Report on Form 10-Q for the fiscal quarter ended August 31, 1999 and incorporated herein by reference. |
| **10.6  | — | Input/Output, Inc. Employee Stock Purchase Plan, filed on March 28, 1997 as Exhibit 4.4 to the Company’s Registration Statement on Form S-8 (Registration No. 333-24125), and incorporated herein by reference. |
| **10.7  | — | Fifth Amended and Restated - 2004 Long-Term Incentive Plan, filed as Appendix A to the definitive proxy statement for the 2010 Annual Meeting of Stockholders of ION Geophysical Corporation, filed on April 21, 2010, and incorporated herein by reference. |
| 10.8    | — | Registration Rights Agreement dated as of November 16, 1998, by and among the Company and The Laitram Corporation, filed on March 12, 2004 as Exhibit 10.7 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2003, and incorporated herein by reference. |
| **10.9  | — | Input/Output, Inc. 1998 Restricted Stock Plan dated as of June 1, 1998, filed on June 9, 1999 as Exhibit 4.7 to the Company’s Registration Statement on S-8 (Registration No. 333-80297), and incorporated herein by reference. |
| **10.10 | — | Input/Output Inc. Non-qualified Deferred Compensation Plan, filed on April 1, 2002 as Exhibit 10.14 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2001, and incorporated herein by reference. |
| **10.11 | — | Input/Output, Inc. 2000 Restricted Stock Plan, effective as of March 13, 2000, filed on August 17, 2000 as Exhibit 10.27 to the Company’s Annual Report on Form 10-K for the fiscal year ended May 31, 2000, and incorporated herein by reference. |
| **10.12 | — | Input/Output, Inc. 2000 Long-Term Incentive Plan, filed on November 6, 2000 as Exhibit 4.7 to the Company’s Registration Statement on Form S-8 (Registration No. 333-49382), and incorporated by reference herein. |
| **10.13 | — | Employment Agreement dated effective as of March 31, 2003, by and between the Company and Robert P. Peebler, filed on March 31, 2003 as Exhibit 10.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| **10.14 | — | First Amendment to Employment Agreement dated September 6, 2006, between Input/Output, Inc. and Robert P. Peebler, filed on September 7, 2006, as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.15 | — | Second Amendment to Employment Agreement dated February 16, 2007, between Input/Output, Inc. and Robert P. Peebler, filed on February 16, 2007 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.16 | — | Third Amendment to Employment Agreement dated as of August 20, 2007 between Input/Output, Inc. and Robert P. Peebler, filed on August 21, 2007 as Exhibit 10.2 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| **10.17 | — | Fourth Amendment to Employment Agreement, dated as of January 26, 2009, between ION Geophysical Corporation and Robert P. Peebler, filed on January 29, 2009 as Exhibit 10.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference. |
| **10.18 | — | Employment Agreement dated effective as of June 15, 2004, by and between the Company and David L. Roland, filed on August 9, 2004 as Exhibit 10.5 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2004, and incorporated herein by reference. |
| **10.19 | — | GX Technology Corporation Employee Stock Option Plan, filed on August 9, 2004 as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2004, and incorporated herein by reference. |
| 10.20   | — | Concept Systems Holdings Limited Share Acquisition Agreement dated February 23, 2004, filed on March 5, 2004 as Exhibit 2.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 10.21   | — | Registration Rights Agreement by and between ION Geophysical Corporation and 1236929 Alberta Ltd. dated September 18, 2008, filed on November 7, 2008 as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q and incorporated herein by reference. |
| **10.22 | — | Form of Employment Inducement Stock Option Agreement for the Input/Output, Inc. - Concept Systems Employment Inducement Stock Option Program, filed on July 27, 2004 as Exhibit 4.1 to the Company’s Registration Statement on Form S-8 (Reg. No. 333-117716), and incorporated herein by reference. |
| **10.23 | — | Form of Employee Stock Option Award Agreement for ARAM Systems Employee Inducement Stock Option Program, filed on November 14, 2008 as Exhibit 4.4 to the Company’s Registration Statement on Form S-8 (Registration No. 333-155378) and incorporated herein by reference. |

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| **10.24 | — | Input/Output, Inc. 2003 Stock Option Plan, dated March 27, 2003, filed as Appendix B of the Company’s definitive proxy statement filed with the SEC on April 30, 2003, and incorporated herein by reference. |
| **10.25 | — | Form of Employment Inducement Stock Option Agreement for the Input/Output, Inc. - GX Technology Corporation Employment Inducement Stock Option Program, filed on April 4, 2005 as Exhibit 4.1 to the Company’s Registration Statement on Form S-8 (Reg. No. 333-123831), and incorporated herein by reference. |
| **10.26 | — | ION Stock Appreciation Rights Plan dated November 17, 2008, filed as Exhibit 10.47 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2008, and incorporated herein by reference. |
| 10.27   | — | Canadian Master Loan and Security Agreement dated as of June 29, 2009 by and among ICON ION, LLC, as lender, ION Geophysical Corporation and ARAM Rentals Corporation, a Nova Scotia corporation, filed on August 6, 2009 as Exhibit 10.3 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2009, and incorporated herein by reference. |
| 10.28   | — | Master Loan and Security Agreement (U.S.) dated as of June 29, 2009 by and among ICON ION, LLC, as lender, ION Geophysical Corporation and ARAM Seismic Rentals, Inc., a Texas corporation, filed on August 6, 2009 as Exhibit 10.4 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2009, and incorporated herein by reference. |
| 10.29   | — | Registration Rights Agreement dated as of October 23, 2009 by and between ION Geophysical Corporation and BGP Inc., China National Petroleum Corporation filed on March 1, 2010 as Exhibit 10.54 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2009, and incorporated herein by reference. |
| 10.30   | — | Stock Purchase Agreement dated as of March 19, 2010, by and between ION Geophysical Corporation and BGP Inc., China National Petroleum Corporation, filed on March 31, 2010 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 10.31   | — | Investor Rights Agreement dated as of March 25, 2010, by and between ION Geophysical Corporation and BGP Inc., China National Petroleum Corporation, filed on March 31, 2010 as Exhibit 10.2 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 10.32   | — | Share Purchase Agreement dated as of March 24, 2010, by and among ION Geophysical Corporation, INOVA Geophysical Equipment Limited and BGP Inc., China National Petroleum Corporation, filed on March 31, 2010 as Exhibit 10.3 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 10.33   | — | Joint Venture Agreement dated as of March 24, 2010, by and between ION Geophysical Corporation and BGP Inc., China National Petroleum Corporation, filed on March 31, 2010 as Exhibit 10.4 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.34 | — | Fifth Amendment to Employment Agreement dated June 1, 2010, between ION Geophysical Corporation and Robert P. Peebler, filed on June 1, 2010 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.35 | — | Employment Agreement dated August 2, 2011, effective as of January 1, 2012, between ION Geophysical Corporation and R. Brian Hanson, filed on November 3, 2011 as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2011, and incorporated herein by reference. |
| **10.36 | — | Employment Agreement dated effective as of November 28, 2011, between ION Geophysical Corporation and Gregory J. Heinlein, filed on December 1, 2011 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.37 | — | First Amendment to Credit Agreement and Loan Documents dated May 29, 2012, filed on May 29, 2012 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.38 | — | Consulting Services Agreement dated January 1, 2013, between ION Geophysical Corporation and ThePeebler Group LLC, filed on January 4, 2013 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| **10.39 | — | Amended and Restated 2013 Long-Term Incentive Plan. |
| 10.40   | — | Purchase Agreement, dated May 8, 2013, among ION Geophysical Corporation, the subsidiary guarantors named therein and Citigroup Global Markets Inc. and Wells Fargo Securities, LLC, as representatives of the initial purchasers named therein, filed on May 13, 2013 as Exhibit 10.1 to the Company’s Current Report on Form 8-K and incorporated herein by reference |

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| 10.41                                                      | — | Second Lien Intercreditor Agreement by and among China Merchants Bank Co., Ltd., New York Branch, as administrative agent, first lien representative for the first lien secured parties and collateral agent for the first lien secured parties, Wilmington Trust Company, National Association, as trustee and second lien representative for the second lien secured parties, and U.S. Bank National Association, as collateral agent for the second lien secured parties, and acknowledged and agreed to by ION Geophysical Corporation and the other grantors named therein, filed on May 13, 2013 as Exhibit 10.2 to the Company’s Current Report on Form 8-K and incorporated herein by reference |
| 10.42                                                      | — | Revolving Credit and Security Agreement dated as of August 22, 2014 among PNC Bank, National Association, as agent for lenders, the lenders from time to time party thereto, as lenders, and PNC Capital Markets LLC, as lead arranger and bookrunner, with ION Geophysical Corporation, ION Exploration Products (U.S.A.), Inc., I/O Marine Systems, Inc. and GX Technology Corporation, as borrowers, filed on November 6, 2014 as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2014, and incorporated herein by reference. |
| **10.43                                                    | — | Transition and Separation Agreement dated effective as of October 30, 2014, by and between ION Geophysical Corporation and Gregory J. Heinlein. |
| **10.44                                                    | — | Employment Agreement dated effective as of November 13, 2014, between ION Geophysical Corporation and Steve Bate. |
| **10.45                                                    | — | Form of Rights Agreement dated March 1, 2015 issued under the ION Stock Appreciation Rights Plan dated November 17, 2008, filed on May 7, 2015 as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2015, and incorporated herein by reference. |
| 10.46                                                      | — | First Amendment to Revolving Credit and Security Agreement dated as of August 4, 2015 among PNC Bank, National Association, as lender and agent, the lenders from time to time party thereto, as lenders, with ION Geophysical Corporation, ION Exploration Products (U.S.A.), Inc., I/O Marine Systems, Inc. and GX Technology Corporation, as borrowers, filed on August 6, 2015 as Exhibit 10.1 to the Company’s Current Report on Form 8-K, and incorporated herein by reference. |
| 21.1                                                       | — | Subsidiaries of the Company. |
| *23.1                                                      | — | Consent of Grant Thornton LLP. |
| 23.2                                                       | — | Consent of Ernst & Young LLP. |
| 24.1                                                       | — | The Power of Attorney is set forth on the signature page hereof. |
| 25.1                                                       | — | Registration Statement (Form S-4 No. 333-194110) of ION Geophysical Corporation, and incorporated herein by reference. |
| *31.1                                                      | — | Certification of Chief Executive Officer Pursuant to Rule 13a-14(a) or Rule 15d-14(a). |
| *31.2                                                      | — | Certification of Chief Financial Officer Pursuant to Rule 13a-14(a) or Rule 15d-14(a). |
| *32.1                                                      | — | Certification of Chief Executive Officer Pursuant to 18 U.S.C. §1350. |
| *32.2                                                      | — | Certification of Chief Financial Officer Pursuant to 18 U.S.C. §1350. |
| 101                                                        | — | The following materials are formatted in Extensible Business Reporting Language (XBRL): (i) Consolidated Balance Sheets at December 31, 2015 and 2014, (ii) Consolidated Statements of Operations for the years ended December 31, 2015, 2014 and 2013, (iii) Comprehensive Income (Loss) for the years ended December 31, 2015, 2014 and 2013, (iv) Consolidated Statements of Cash Flows for the years ended December 31, 2015, 2014 and 2013, (v) Consolidated Statements of Stockholders’ Equity for the years ended December 31, 2015, 2014 and 2013, (vi) Footnotes to Consolidated Financial Statements and (vii) Schedule II - Valuation and Qualifying Accounts. |
|                                                       |   |   |
|    *Filed herewith.                         |
| **Management contract or compensatory plan or arrangement. |