<PAGE>

                         EQUIPMENT PURCHASE AGREEMENT

     THIS EQUIPMENT PURCHASE AGREEMENT (the "AGREEMENT") is executed as of
the date set forth below by and between INPUT/OUTPUT, INC., a Delaware
corporation, and its wholly-owned subsidiary, GLOBAL CHARTER CORPORATION, a
Delaware corporation (together, "SELLER") and MITCHAM INDUSTRIES, INC., a
Texas corporation ("BUYER").

                                   RECITALS:

A.   Seller is primarily engaged in the business of manufacturing and selling
     seismic data acquisition equipment and related products, and additionally
     has been engaged in the business of leasing its equipment to its customers
     under lease/purchase agreements.

B.   Buyer is primarily engaged in the business of leasing seismic equipment,
     including equipment and products manufactured by Seller, to its customers.

C.   Seller has agreed to sell to Buyer, and Buyer has agreed to purchase from
     Seller, certain equipment and products owned by Seller that comprises a
     substantial portion of Seller's inventory held for rental to customers more
     particularly described in SCHEDULE 1 attached hereto (the "RENTAL
     INVENTORY").

D.   Certain of the Rental Inventory (the "LEASED INVENTORY") is subject to
     certain leases and rental agreements (the "LEASES"), which Leased
     Inventory and Leases are more particularly described on SCHEDULE 2
     attached hereto, and Seller has agreed to assign the Leases to Buyer.

E.   As additional consideration for the purchase and sale of the Rental
     Inventory, Seller and Buyer have agreed to enter into a Preferred Supplier
     Agreement ("SUPPLIER AGREEMENT") pursuant to which Buyer will commit to
     purchase certain amounts of Products (defined therein) manufactured by
     Seller over the term of the Supplier Agreement and Seller will agree to
     give certain preferred pricing to Buyer in the form of discounts and
     credits.  The parties have agreed to the basic terms and conditions of the
     Supplier Agreement as set forth on EXHIBIT A attached hereto (the "SUMMARY
     OF TERMS"), which will be memorialized in a definitive Supplier Agreement
     to be executed by the parties after the Effective Date.

     NOW, THEREFORE, in consideration of the foregoing, and other good and
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, Seller and Buyer hereby agree as follows:

     1.   DEFINED TERMS.  As used in this Agreement, the following terms shall
have the meanings set forth below:

                                       1
<PAGE>

     "ADDITIONAL INVENTORY" means the equipment and products owned by Seller
and leased to customers pursuant to the Additional Leases, as set forth on
SCHEDULE 3 attached hereto.

     "ADDITIONAL LEASES" means those rental and lease/purchase agreements
between Seller and various customers for the rental of Additional Inventory,
as described in SCHEDULE 3 attached hereto.

     "ASSIGNMENT" means the Assignment of Leases in the form attached hereto
as EXHIBIT B.

     "BILL OF SALE" means the Bill of Sale in the form attached hereto as
EXHIBIT C.

     "EFFECTIVE DATE" means May 29, 1998.

     "EQUIPMENT" means, collectively, the Rental Inventory and the Additional
Inventory.

     "LEASED INVENTORY" means that portion of the Rental Inventory that is
leased to customers pursuant to the Leases, and described in SCHEDULE 3
attached hereto.

     "LEASES" means those rental and lease/purchase agreements between Seller
and various customers for the rental of Leased Inventory, as described in
SCHEDULE 3 attached hereto.

     "RENTAL INVENTORY" means the equipment and products of Seller described
in SCHEDULE 1 attached hereto.

     "RENTAL FLEET" means, collectively, the Rental Inventory and the Leases,
and following the Second Closing Date, if any, the Additional Inventory and
the Additional Leases.

     "SECOND CLOSING DATE" has the meaning given that term in SECTION 4.

     "SUMMARY OF TERMS" means the basic terms and conditions that have been
agreed by Buyer and Seller to be contained in the Supplier Agreement and
which are attached hereto as EXHIBIT A.

     "SUPPLIER AGREEMENT" means the Preferred Supplier Agreement to be
entered into by Buyer and Seller after the Effective Date, which shall
incorporate the terms and conditions (among other terms) set forth in the
Summary of Terms.

     2.   SALE OF RENTAL INVENTORY.  On the Effective Date, Seller shall sell
to Buyer and Buyer shall purchase from Seller, the Rental Inventory.  The
purchase price for the Rental Inventory shall be $15,000,000.  In addition,
on the Effective Date, Seller shall assign the Leases to Buyer.

                                       2
<PAGE>

     3.   CLOSING.  The closing of the transactions contemplated herein
("CLOSING") shall take place at the offices of Seller's counsel, or at such
other place as may be agreed by the parties, on the Effective Date.  At the
Closing:

          (a)  Buyer shall deliver to Seller:

               (i)   the sum of $2,250,000 (being 15% of the purchase price for
          the Rental Inventory), in cash or immediately available funds, and the
          remainder of the purchase price for the Rental Equipment shall be due
          and payable to Seller in cash or immediately available funds
          immediately upon completion of the definitive form of the Supplier
          Agreement.

               (ii)  an executed counterpart of the Assignment, executed by
          Buyer.

          (b)  Seller shall deliver to Buyer:

               (i)   the Rental Inventory (other than the Leased Inventory);
          provided, however, that certain items of Rental Inventory are in
          transit to Seller from customers, and Seller will deliver those items
          of Rental Inventory to Buyer promptly following receipt thereof;

               (ii)  the Bill of Sale executed by Seller with respect to the
          Rental Inventory.

               (iii) an executed counterpart of the Assignment executed by
          Seller; and

               (iv)  the original of all Leases that are in Seller's possession,
          and if the original of such Leases are not in Seller's possession, a
          copy of those Leases.

     4.   SALE OF ADDITIONAL LEASED INVENTORY.  Seller and Buyer acknowledge
and agree that: (a) the Leased Inventory does not constitute all of the
equipment and products owned by Seller that are leased to Seller's customers,
(b) certain other equipment and products constituting the Additional
Inventory have been leased by Seller to certain customers pursuant to the
Additional Leases, and (c) due to incomplete documentation with respect to
the Additional Inventory, Seller is not in a position to deliver and assign
the Additional Leases on the Effective Date.  Seller intends to have the
documentation with respect to the Additional Inventory and Additional Leases
completed and assembled within fifteen (15) days after the Effective Date.
Seller hereby grants to Buyer the right and option to purchase the Additional
Equipment and the Additional Leases on or before the date that is thirty (30)
days after the Effective Date (the "SECOND CLOSING DATE").  If Buyer elects
to exercise its option and purchase the Additional Inventory prior to the
Second Closing Date, Seller and Buyer shall execute and deliver (i) an
Assignment of Leases with respect to the Additional Leases in substantially
the same form as the Assignment and (ii) a Bill of Sale with respect to the
Additional Inventory in substantially the

                                       3
<PAGE>

same form as the Bill of Sale.  The purchase price for the Additional
Inventory shall be determined by agreement of the parties.

     5.   REPRESENTATIONS AND WARRANTIES OF SELLER.  Seller hereby represents
and warrants to Buyer as follows:

          (a)  Seller is authorized to executed and deliver this Agreement and
     to perform its obligations hereunder.

          (b)  Seller is the owner of the Rental Inventory and the Additional
     Inventory, and is the lessor under the Leases and the Additional Leases.

     6.   REPRESENTATIONS, WARRANTIES AND ACKNOWLEDGMENTS OF BUYER.  Buyer
hereby represents, warrants and acknowledges to Seller as follows:

          (a)  Buyer is authorized to executed and deliver this Agreement and to
     perform its obligations hereunder.

          (b)  Except for the limited warranties set forth in SECTION 8 below,
     Buyer hereby acknowledges that Buyer is purchasing the Rental Fleet, and
     those assets and property shall be conveyed and transferred to Buyer, "AS
     IS, WHERE IS, AND WITH ALL FAULTS" and specifically and expressly without
     any warranties, representations, or guarantees, either express or implied,
     of any kind, nature, or type whatsoever from or on behalf of Seller.
     SELLER HAS NOT, DOES NOT, AND WILL NOT WITH RESPECT TO THE RENTAL FLEET,
     MAKE ANY WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED, OR ARISING BY
     OPERATION OF LAW, INCLUDING, BUT IN NO WAY LIMITED TO, ANY WARRANTY OF
     CONDITION, MERCHANTABILITY, HABITABILITY, OR FITNESS FOR A PARTICULAR USE,
     OR WITH RESPECT TO THE VALUE, PROFITABILITY, OR MARKETABILITY OF THE RENTAL
     FLEET.

     7.   PREFERRED SUPPLIER AGREEMENT.  As consideration for the execution
and consummation of this Agreement, Buyer and Seller have agreed to enter
into a Supplier Agreement on the terms set forth in the Summary of Terms.
Buyer and Seller acknowledge and agree that (a) the Summary of Terms contain
the basic business terms that the parties have agreed upon, but that
additional terms and conditions may be reasonably required by the respective
parties and their counsel, and (b) they will negotiate the other terms of the
Supplier Agreement in good faith and use reasonable efforts to have the
definitive form of the Supplier Agreement signed by the parties by June 30,
1998.  Seller agrees that the purchase price for the Equipment will count
towards the Buyer's minimum annual purchase requirement for Year 1 under the
Supplier Agreement.

                                       4
<PAGE>

     8.   PRODUCT WARRANTIES.  The sale of the Rental Fleet is made without
warranty of any kind, except as set forth in SECTION 5; and provided further
that Seller will provide a limited 90-day warranty on the Rental Inventory
and the Additional Inventory as provided in EXHIBIT D.

     9.   TAXES.  All sales, value added, use, excise and other taxes arising
from the transaction are to be paid by Buyer.  Buyer agrees to indemnify and
hold Seller harmless from and against any liability for such sales, use,
excise, or other taxes arising from the transactions contemplated by this
Agreement.

     10.  EXPORT RESTRICTIONS.  Buyer agrees that it shall comply with any
and all laws, regulations, orders, or other restrictions of the United States
of America relating to the export and re-export of commodities and technical
data which may be imposed from time to time.  Buyer will not export or
re-export, directly or indirectly any products or information with respect to
the Equipment to any destination prohibited by such laws, regulations, orders
or other restrictions without the prior authorization of the appropriate U.S.
Government authorities.  Buyer agrees that its obligations under this section
shall survive Closing.

     11.  PROPRIETARY RIGHTS, LICENSE AND CONFIDENTIALITY.

          (a)  Buyer acknowledges that the Equipment contains certain hardware
     components and software proprietary to Seller.  Seller, for itself and its
     assignees, hereby grants to Buyer a non-exclusive, irrevocable license to
     use the software for the purpose of operating the Equipment.  The license
     granted hereunder is for an undetermined period and shall survive the
     Closing.

          (b)  Buyer acknowledges that any hardware and software proprietary to
     Seller are trade secrets and constitute a valuable asset of Seller.  Buyer
     agrees that it shall exercise at least the same degree of care and
     discretion with respect to the hardware and software as it exercises in
     protecting its own confidential information; that it shall not disclose or
     otherwise make available, without the prior written consent of Seller, the
     hardware or software or any copies of it to any other person and that it
     shall not copy or reproduce the hardware or software.  Buyer agrees that
     this provision shall survive the Closing.

          (c)  Buyer further acknowledges that it shall not, without the prior
     written consent of Seller, divulge any information relating to the terms of
     this Agreement to any third party, except as to the extent required by law,
     and shall take all reasonable action to prevent its employees and all
     others, if any, involved in this Agreement from divulging such information
     to third parties.

     12.  PRORATION OF RENTAL PAYMENTS.  Rental payments under the Leases and
the Additional Leases actually paid to and received by Seller for the month
in which the Closing (or the Second Closing Date) occurs shall be prorated as
of the Effective Date or the Second Closing Date, as appropriate.  Buyer
shall make a diligent attempt after the Closing to collect any rental
payments delinquent at the time of the assignment of the Leases or Additional
Leases in the usual

                                       5
<PAGE>

course of business and shall remit Seller's portion of those collections to
Seller promptly after receipt by Buyer.  Nothing in this subparagraph shall
prohibit, limit or restrict Seller from collecting or attempting to collect
directly from any lessee in any lawful manner after Closing any rents
delinquent as of Closing.

     13.  NOTICES.  Any notice or delivery to be given hereunder by either
party to the other may be effected by personal delivery in writing, certified
mail, postage prepaid, mailgram or telegram, and shall be deemed communicated
as of delivery, unless otherwise provided in this Agreement in accordance
with this paragraph at the address set forth below:

     Seller:         Input/Output, Inc.
                     11104 West Airport, Suite 200
                     Stafford, Texas 77477
                     Attention: Gay Mayeux, Chief Financial Officer

     Buyer:          Mitcham Industries, Inc.
                     P.O. Box 1175
                     Huntsville, Texas 77342
                     Attention: Bill F. Mitcham, Jr.

     14.  MISCELLANEOUS PROVISIONS.

          (a)  ENTIRE AGREEMENT.  This Agreement constitutes the entire
     agreement between Seller and Buyer with respect to the purchase and sale of
     the Equipment and no representation or statement not contained herein shall
     be binding upon Seller or Buyer as a warranty or otherwise, unless in
     writing and executed by the party to be bound thereby. This Agreement shall
     be binding upon and inure to the benefit of the parties hereto and their
     respective successors and assigns.

          (b)  GOVERNING LAW.  This Agreement shall be construed in accordance
     with the laws of the State of Texas.

          (c)  RISK OF LOSS.  The sale of the Equipment (other than Leased
     Inventory and Additional Inventory) hereunder will be F.O.B. Seller's plant
     in Stafford, Texas, with Buyer being responsible for the cost of shipping
     and transporting the Equipment.

          (d)  BINDING EFFECT.  This Agreement is binding upon and inures to the
     benefit of Seller and Buyer and their respective successors and assigns.

          (e)  FURTHER ACTS.  In addition to the acts and deeds recited in this
     Agreement and contemplated to be performed, executed and/or delivered by
     Seller or Buyer, Seller and Buyer agree to perform, execute and/or deliver
     or cause to be performed, executed and/or delivered at the Closing or after
     the Closing any and all further acts, deeds and

                                       6
<PAGE>

     assurances as are reasonably necessary to consummate the transactions
     contemplated hereby.

          (f)  TIME OF THE ESSENCE.  It is expressly agreed by Buyer and Seller
     that time is of the essence with respect to this Agreement.

          (g)  ATTORNEY'S FEES.  If either party hereto employs an attorney to
     enforce or defend its rights hereunder, the prevailing party shall be
     entitled to recover its reasonable attorney's fees.

          (h)  MULTIPLE COUNTERPARTS.  This Agreement may be executed in any
     number of counterparts, all of which taken together shall constitute one
     and the same agreement, and any of the parties to this Agreement may
     execute this Agreement by signing any of the counterparts.









                                       7
<PAGE>

     EXECUTED as of May 29, 1998.

                                   INPUT/OUTPUT, INC., a Delaware corporation


                                   By:  /s/ DENNIS N. JORDHOY
                                       ----------------------------------------
                                        Dennis N. Jordhoy, Vice President-Sales


                                   GLOBAL CHARTER CORPORATION, a Delaware
                                   corporation


                                   By:  /s/ RONALD A. HARRIS
                                       ----------------------------------------
                                        Ronald A. Harris, President


                                   MITCHAM INDUSTRIES, INC., a Texas corporation

                                   By:  /s/ BILL F. MITCHAM
                                       ----------------------------------------
                                        Bill F. Mitcham, President and Chief
                                        Executive Officer




                                       8
<PAGE>

                                   EXHIBIT A

                                SUMMARY OF TERMS

I/O has proposed to sell its existing rental fleet to Mitcham.  I/O also 
proposes to restructure its existing agreements with Mitcham by entering into 
a new Preferred Supplier Agreement (the "NEW AGREEMENT") with Mitcham (which 
will replace the existing Exclusive Lease Referral Agreement, as amended), on 
the following terms and conditions:

1.   SALE OF RENTAL FLEET.  I/O will sell its rental fleet to Mitcham (including
     Products currently under lease/purchase agreements to I/O's customers) for
     a price to be determined by the parties.  Products currently under
     lease/purchase agreements will be sold subject to such lease/purchase
     agreements, which will be assigned to Mitcham.

2.   MINIMUM ANNUAL PURCHASES.  I/O will agree to sell to Mitcham and Mitcham
     will agree to purchase from I/O, during the Term of the New Agreement,
     certain minimum amounts of new and used I/O Products, as follows:

<TABLE>
<S>                                                         <C>
     May 26, 1998 through May 31, 1999  ("YEAR 1")          $30 million
     June 1, 1999 through May 31, 2000  ("YEAR 2")          $25 million
     June 1, 2000 through May 31, 2001  ("YEAR 3")          $25 million
     June 1, 2001 through May 31, 2002  ("YEAR 4")          $25 million
     June 1, 2002 through May 31, 2003  ("YEAR 5")          $25 million
</TABLE>

     The above amounts shall be based on I/O's list prices for its Products, as
     published on the date of the New Agreement.  Any purchases in excess of the
     annual minimum aggregate may be applied to purchase commitments for the
     next year.  If Mitcham fails to purchase Products in the minimum amount
     during any fiscal Year as set forth above, I/O shall have the right to
     terminate the New Agreement.

3.   TERM.  Effective as of May 26, 1998 through May 31, 2003.

4.   I/O PRODUCTS.  "PRODUCTS" covered under the New Agreement will be all
     products currently manufactured and sold by I/O as of the date of the New
     Agreement, and shall not refer to any new products introduced and
     manufactured by I/O after such date; provided, however, that I/O will agree
     to negotiate with Mitcham for the inclusion of any such new products within
     the scope of the New Agreement on a case-by-case basis. There will be no
     territory limitations under the New Agreement.

5.   DISCOUNTS AND CREDITS.  Mitcham shall be entitled to certain discounts
     against purchases made pursuant to the terms of the New Agreement.  The
     discount to which Mitcham will be entitled for each Product type purchased
     will be as set forth on SCHEDULE A.  In addition, if Mitcham achieves the
     minimum annual purchase levels set forth above during each Year, Mitcham
     shall be entitled to a credit against the purchase price for future
     purchases of Products in the amount of 10% of the purchase price of
     Products purchased during that fiscal Year.  The credit must be used during
     the next fiscal Year or it will be waived.  Fifty percent (50%) of Products
     purchased with the credit will count toward Mitcham's minimum annual
     purchase requirements for that fiscal Year.

                                       9
<PAGE>

6.   RENTAL RESTRICTIONS.  I/O will not offer to rent Products to third parties
     during the Term, without the express written consent of Mitcham; provided,
     however, Seller shall have the right to rent Products to third parties for
     experimental or developmental purposes.  I/O agrees to refer rental
     inquiries for Products to Mitcham during the Term of the New Agreement.   
     Mitcham agrees to use best efforts to promote I/O Products during the term
     of the New Agreement.

7.   RESALE RESTRICTIONS.  The parties understand and agree that Mitcham is in
     the business of leasing Products to its rental customers, and is not
     acquiring Products for resale to third parties.  As part of the
     consideration for the discounts and credits being granted to Mitcham,
     Mitcham agrees that it will not offer for resale to third parties, without
     the prior written consent of I/O, any Products (other than Products that
     are purchased by Mitcham's rental customers pursuant to purchase options
     granted under rental agreements) that it has purchased from I/O that were
     manufactured less than 3 years from the date of the offer.  

8.   PAYMENT TERMS.  Payment of the purchase price for Products shall be net 30
     days; provided, however, that Mitcham will be entitled to an additional 2%
     discount from the purchase price if payment thereof is received by I/O
     within 10 days from date of shipment.  In addition, if Products purchased
     at any one time have a purchase price of $5 million or more, Mitcham will
     grant to I/O a purchase money security interest in those Products to secure
     payment of the purchase price thereof.  Mitcham agrees to execute all
     financing statements required by I/O to perfect its security interests at
     the time of sale.

9.   RIGHT OF FIRST REFUSAL.  Mitcham shall grant to I/O a right of first
     refusal to purchase any Products (other than Products that are proposed to
     be purchased from Mitcham pursuant to a lease/purchase agreement with one
     of Mitcham's customers) that Mitcham desires to sell (subject to the resale
     restrictions), but only with respect to Products for which the sale price
     exceeds $1 million.  I/O shall have the right to match any bona fide third
     party offer to purchase those Products on the same terms and conditions.

10.  TRAINING; MAINTENANCE AND REPAIRS.  I/O will offer training courses for
     Mitcham, and its employees and representatives of customers that lease
     Products from Mitcham, at a 25% discount to I/O published rates for those
     services.  I/O will provide maintenance and repairs to all Products, at I/O
     published rates.

11.  WARRANTIES.  I/O will warrant all new Products based upon I/O's standard
     limited warranty, as the same is revised from time to time.  A limited 
     90-day warranty will be given on used Products sold to Mitcham.

12.  PRESS RELEASES.  Neither party will issue any public announcement or press
     release regarding the New Agreement or any purchase of Products thereunder
     without the written approval of the other party.

13.  PREFERRED PRICING.  In consideration for Mitcham's commitment to make the
     minimum annual purchases described above, I/O agrees that it will not,
     during the Term, offer pricing for Products to any other customer that is
     in the same line of business as Mitcham (i.e., seismic equipment rentals)
     that is more favorable than that offered to Mitcham under the New
     Agreement.

                                       10
<PAGE>

                                  SCHEDULE A
                       to Exhibit A -- Summary of Terms 
                                       
                              DISCOUNT SCHEDULE

<TABLE>
-------------------------------------------------------------------------------
            PRODUCT                                DISCOUNT
-------------------------------------------------------------------------------
<S>                                     <C>
MRX Electronics                         25%
-------------------------------------------------------------------------------
RSR Electronics                         15%
-------------------------------------------------------------------------------
MSX Electronics                         10%
-------------------------------------------------------------------------------
Cables                                  15%
-------------------------------------------------------------------------------
Geophone and Hydrophone Products        15%
-------------------------------------------------------------------------------
Sleeve Guns                             10%
-------------------------------------------------------------------------------
Vibrators                               Negotiated on a case by case basis
-------------------------------------------------------------------------------
</TABLE>





                                       11
<PAGE>

                                   EXHIBIT B

                              ASSIGNMENT OF LEASES

     THIS ASSIGNMENT OF LEASES (the "ASSIGNMENT") is executed by and between 
INPUT/OUTPUT, INC., a Delaware corporation, and its wholly-owned subsidiary, 
GLOBAL CHARTER CORPORATION, a Delaware corporation (together, "ASSIGNOR") and 
MITCHAM INDUSTRIES, INC., a Texas corporation  ("ASSIGNEE")

                                   RECITALS:

A.   Assignor and Assignee have entered into that certain Equipment Purchase
     Agreement ("PURCHASE AGREEMENT"), pursuant to which Assignor has sold to
     Assignee, among other property, certain equipment and products manufactured
     by Assignor and leased to Assignor's customers pursuant to certain
     lease/purchase and rental agreements more particularly described on EXHIBIT
     A attached hereto (the "EXISTING LEASES").

B.   In accordance with the terms of the Purchase Agreement, Assignor has agreed
     to assign and transfer all of its right, title and interest in and to the
     Existing Leases to Assignee.

     NOW, THEREFORE, in consideration of the sum of Ten and No/100 Dollars 
($10.00) in hand paid and other good and valuable consideration, the receipt 
of which is hereby acknowledged, Assignor and Assignee hereby agree as 
follows:

     1.   ASSIGNMENT OF LEASES.  Assignor hereby assigns, transfers, sets 
over and conveys to Assignee, all of Assignor's right, title and interest in 
and to the Existing Leases.  Assignee hereby assumes and agrees to perform 
all of Assignor's obligations under the Existing Leases that arise thereunder 
from and after the date hereof.

     2.   INDEMNITIES.

          (a)  Assignor hereby agrees to defend, indemnify and hold Assignee
     harmless from any liability, damages, causes of action, expenses and
     attorneys' fees incurred by Assignee by reason of the failure of Assignor
     prior to the effective date hereof to fulfill, perform and discharge all of
     the various commitments, obligations and liabilities of Assignor under and
     by virtue of the Existing Leases assigned hereunder, but only to the extent
     that such failure of Assignor under the Existing Leases accrued and arose
     prior to the effective date hereof.

          (b)  Assignee hereby agrees to defend, indemnify and hold Assignor
     harmless from any liability, damages, causes of action, expenses and
     attorneys' fees incurred by Assignor by reason of the failure of Assignee
     on or after the effective date hereof to fulfill, perform and discharge all
     of the various commitments, obligations and liabilities of Assignee herein
     assumed under and by virtue of the Existing Leases assigned 

                                       12
<PAGE>

     hereunder, but only to the extent that such failure of Assignee under the 
     Existing Leases accrued and arose on or after the effective date hereof.

     Executed and effective as of the 31 day of May, 1998.


                                   INPUT/OUTPUT, INC., a Delaware corporation 



                                   By:  /s/ DENNIS N. JORDHOY
                                      -----------------------------------------
                                        Dennis N. Jordhoy, Vice President-Sales



                                   GLOBAL CHARTER CORPORATION, a Delaware
                                   corporation



                                   By:  /s/ RONALD A. HARRIS
                                      -----------------------------------------
                                        Ronald A. Harris, President
                                   


                                   MITCHAM INDUSTRIES, INC., a Texas corporation


                                   By:  /s/ BILL F. MITCHAM
                                      -----------------------------------------
                                        Bill F. Mitcham, President and Chief
                                        Executive Officer

                                       13
<PAGE>
                                       
                                  Exhibit A
                                       
                     TO EXHIBIT B -- ASSIGNMENT OF LEASES
                                       
                                       
                               EXISTING LEASES

<TABLE>
--------------------------------------------------------------------------------
<S>                 <C>                 <C>
Lease Number        Date of Lease       Customer
--------------------------------------------------------------------------------
R9804010            5/26/98             Acadian Geophysical Svcs., Inc.
--------------------------------------------------------------------------------
R9804090            5/26/98             Acadian Geophysical Svcs., Inc.
--------------------------------------------------------------------------------
R9712111            12/22/97            Datum Exploration, Ltd.
--------------------------------------------------------------------------------
R9801090            00/05/98            Mitcham Industries
--------------------------------------------------------------------------------
R9804210            5/26/98             Paragon Geophysical Services, Inc.
--------------------------------------------------------------------------------
R9610170            10/17/96            Suelopetrol, C.A.
--------------------------------------------------------------------------------
R9805200            5/20/98             Universal Seismic Associates
--------------------------------------------------------------------------------
R9705220            5/22/97             Veritas DGC Land, Inc., Suc., Arg.
--------------------------------------------------------------------------------
R9705300            8/12/97             Veritas DGC Land, Inc.
--------------------------------------------------------------------------------
R9804300            4/30/98             Veritas DGC Land, Inc.
--------------------------------------------------------------------------------
R9706100            8/12/97             Veritas DGC Land, Inc. 
--------------------------------------------------------------------------------
R9707240            9/30/97             Veritas DGC Land, Inc.(Ecuador)
--------------------------------------------------------------------------------
R9711250            8/20/98             Veritas DGC Land, Inc.
--------------------------------------------------------------------------------
R9805010            5/8/98              Western Geophysical
--------------------------------------------------------------------------------
R9804030            5/1/98              Western Geophysical Company
--------------------------------------------------------------------------------
</TABLE>





                                       14
<PAGE>

                                   EXHIBIT C

                                  BILL OF SALE

     THIS BILL OF SALE (the "BILL OF SALE") is executed by and between 
INPUT/OUTPUT, INC., a Delaware corporation, and its wholly-owned subsidiary, 
GLOBAL CHARTER CORPORATION, a Delaware corporation (together, "SELLER") and 
MITCHAM INDUSTRIES, INC., a Texas corporation ("BUYER")

                                   RECITALS:

A.   Seller and Buyer have entered into that certain Equipment Purchase
     Agreement ("PURCHASE AGREEMENT"), pursuant to which Seller has agreed to
     sell to Buyer certain equipment and products manufactured by Seller, which
     consists of certain equipment and products held as inventory for rental to
     Seller's customers, more particularly described on SCHEDULE 1 attached
     hereto (the "RENTAL INVENTORY").

B.   In accordance with the terms of the Purchase Agreement, Seller has agreed
     to execute and deliver this Bill of Sale to Buyer to evidence the transfer
     of title to the Rental Inventory.

     NOW, THEREFORE, in consideration of the sum of Ten and No/100 Dollars 
($10.00) in hand paid and other good and valuable consideration, the receipt 
of which is hereby acknowledged, Seller and Buyer hereby agree as follows:

     1.   CONVEYANCE.  Seller hereby assigns, transfers, sets over and 
conveys to Buyer, all of Seller's right, title and interest in and to the 
Rental Inventory. Buyer understands and acknowledges that certain of the 
Rental Inventory is subject to the rights of lessees under certain 
lease/purchase and rental agreements, more particularly described as the 
"LEASES" and attached to the Purchase Agreement as SCHEDULE 2.

     2.   NO WARRANTIES.  Except for Seller's 90-day standard limited 
warranty with respect to the Rental Inventory set forth in the Purchase 
Agreement, Buyer hereby acknowledges that Buyer is purchasing the Rental 
Inventory, and the Rental Inventory is being conveyed and transferred to 
Buyer, "AS IS, WHERE IS, AND WITH ALL FAULTS" and specifically and expressly 
without any warranties, representations, or guarantees, either express or 
implied, of any kind, nature, or type whatsoever from or on behalf of Seller. 
SELLER HAS NOT, DOES NOT, AND WILL NOT WITH RESPECT TO THE RENTAL INVENTORY, 
MAKE ANY WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED, OR ARISING BY 
OPERATION OF LAW, INCLUDING, BUT IN NO WAY LIMITED TO, ANY WARRANTY OF 
CONDITION, MERCHANTABILITY, HABITABILITY, OR FITNESS FOR A PARTICULAR USE, OR 
WITH RESPECT TO THE VALUE, PROFITABILITY, OR MARKETABILITY OF THE RENTAL 
INVENTORY.

                                       15
<PAGE>

     Executed and effective as of the 31 day of May, 1998.

                                   INPUT/OUTPUT, INC., a Delaware corporation 


                                   By:  /s/ DENNIS N. JORDHOY
                                      -----------------------------------------
                                        Dennis N. Jordhoy, Vice President-Sales


                                   GLOBAL CHARTER CORPORATION, a Delaware
                                   corporation


                                   By:  /s/ RONALD A. HARRIS
                                      -----------------------------------------
                                        Ronald A. Harris, President
                                   

                                   MITCHAM INDUSTRIES, INC., a Texas corporation

                                   By:  /s/ BILL F. MITCHAM
                                      -----------------------------------------
                                        Bill F. Mitcham, President and Chief
                                        Executive Officer

                                       16
<PAGE>

                                  EXHIBIT D
                                       
                              INPUT/OUTPUT, INC.
                          STANDARD LIMITED WARRANTY

GENERAL.  Input/Output, Inc. ("I/O") warrants each product that it or its 
subsidiaries manufacture ("Product") against defects in material and 
workmanship under normal use and service for the specified time period listed 
below ("Warranty Period"), in each case commencing upon the date of original 
purchase (or, in the event of a purchase by exercise of an option to purchase 
under a rental arrangement, commencing upon the first day of the rental 
period):

<TABLE>
        SPECIFIED PRODUCT                                   WARRANTY PERIOD
        -----------------                                   ---------------
<S>                                                         <C>
        Software (media only) (see below)                   30 Days
        Air Guns (solenoid metal parts only)                30 Days
        Hydrophones and Geophones                           See Addendum "A"
        Marine Cables and Connectors                        90 Days
        Streamer Cable - Stretch Sections                   90 Days
        Lead-ins: Fiber Optic                               90 Days
        Lead-ins: Analog                                    180 Days
        Land Cables and Connectors                          180 Days
        Air Guns (metal parts only)                         180 Days
        Hose Bundles                                        180 Days
        Battery Packs                                       180 Days
        Marine Remote Signal Conditioner
             (MSX and Bottom Cable Units)                   One Year
        Remote Signal Conditioner (MRX,RSR,ALX
             (and MLX Units)                                Two Years
        Vibrators and other Off-Road Vehicles (see below)   One Year
        All Other I/O Products                              One Year
</TABLE>

I/O, at its option, will either repair, rebuild, adjust or replace the 
Product or Product parts during the Warranty Period in the event the Product 
fails to perform as specified under normal usage, which failure to perform 
has been promptly reported by Purchaser to I/O and determined by I/O to be 
defective in material or workmanship.  Repaired, rebuilt, adjusted or 
replaced Products or component parts are warranted for sixty (60) days or the 
remainder of the original Warranty Period, whichever is longer.  This 
Warranty extends solely to the original end-user purchaser ("Purchaser") of 
the Product.

<PAGE>

SOFTWARE.  With regards to any I/O Software, I/O warrants that, for 30 days 
following the date of original purchase, the media containing the I/O 
Software shall be free from defects in material and workmanship under normal 
use.  I/O's sole and exclusive obligation and liability for any such defect 
with regard to the I/O Software shall be, in I/O's sole discretion, to 
replace the defective media with replacement media or to correct the 
defective media so that it will be free from defects in material and 
workmanship.  Corrected or replaced media on which the I/O Software is 
furnished shall be covered by this Warranty for thirty (30) days after the 
date of shipment to Purchaser of the repaired, corrected or replaced physical 
media.  I/O will have no warranty obligation with regard to any I/O Software 
if (i) the media has been subjected to accident, abuse, or improper use, (ii) 
Purchaser uses defective media or defectively or improperly duplicates the 
I/O Software, or (iii) Purchaser violates the "Restrictions on Use" listed 
below regarding the Software. I/O MAKES NO OTHER REPRESENTATION OR WARRANTY 
OF ANY KIND, EXPRESS OR IMPLIED WITH REGARD TO ANY I/O SOFTWARE AND EXPRESSLY 
DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR 
PURPOSE.  I/O DOES NOT WARRANT THAT I/O SOFTWARE IS ERROR-FREE OR THAT 
OPERATION OF THE I/O SOFTWARE WILL BE UNINTERRUPTED.  The Warranty set forth 
in this paragraph constitutes the only warranty with respect to I/O Software 
and is further subject to the "General Provisions" set forth below; in all 
other respects, I/O Software is provided "AS-IS" and all risk as to the 
quality, performance, capabilities and other requirements of the I/O Software 
is with Purchaser.  For the purposes of this Limited Warranty, I/O Software 
shall be deemed to include, but not be limited to, embedded software which is 
organic to and contained in I/O Products at the time such Products are sold.

VIBRATORS.  This terms of this portion of the Limited Warranty are applicable 
only to Vibrators and other Off-Road Vehicles assembled by I/O ("Vibrators"). 
Subject to the terms of this Limited Warranty, I/O warrants each Vibrator 
vehicle for repairs, including parts and labor, to correct defects in 
materials or workmanship under normal use and service, for a Warranty Period 
of one (1) year from the date of purchase of the Vibrator (or, in the event 
of a purchase by exercise of an option to purchase under a rental 
arrangement, commencing upon the first day of the rental period).  The 
Limited Warranty applicable to Vibrators and their parts shall transfer 
automatically with transfers of vehicle ownership during the Warranty Period. 
I/O's sole responsibility as to Vibrators under this Limited Warranty shall 
be, at its option, to repair, rebuild or replace any item which is determined 
by I/O to be defective in material or workmanship during the Warranty Period 
in the event the item fails to perform as specified under normal usage.  This 
Warranty does not extend to any routine maintenance of the Vibrator or its 
components.  For other limitations applicable to I/O's obligations with 
respect to Vibrators under the terms of this Limited Warranty, see "Items Not 
Covered by this Warranty below."  In addition, the Warranty on items not 
originally manufactured by I/O shall conform to the Warranty, if any, 
extended by the original manufacturer of those items.  I/O MAKES NO 
REPRESENTATIONS REGARDING THE EXTENT, AVAILABILITY OR APPLICABILITY OF 
WARRANTIES PROVIDED BY OUTSIDE MANUFACTURERS. 

<PAGE>

GENERAL PROVISIONS.

THIS AGREEMENT EXPRESSES ALL OF I/O'S RESPONSIBILITIES, WHETHER IN TORT OR IN 
CONTRACT, REGARDING ITS PRODUCTS.  REPAIR, ADJUSTMENT OR REPLACEMENT OF 
PRODUCTS OR PARTS, AT I/O'S OPTION, IS PURCHASER'S EXCLUSIVE REMEDY.  I/O 
SHALL NOT, IN ANY EVENT, BE RESPONSIBLE FOR DAMAGES OR OTHER SUMS IN EXCESS 
OF THE PURCHASE PRICE.  WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, 
UNDER NO CIRCUMSTANCE SHALL I/O BE RESPONSIBLE OR LIABLE IN ANY REGARD WITH 
RESPECT TO DAMAGES FROM LOSS OF USE, LOSS OF TIME, LOSS OF DATA, 
INCONVENIENCE, COMMERCIAL LOSS, LOST PROFITS OR SAVINGS, OR OTHER INCIDENTAL, 
SPECIAL OR CONSEQUENTIAL DAMAGES CLAIMED BY PURCHASER TO ARISE OUT OF THE USE 
OR INABILITY TO USE THE PRODUCT, EVEN IF PURCHASER HAS BEEN ADVISED OF THE 
POSSIBILITY OF SUCH DAMAGES.  ALL OTHER WARRANTIES, WHETHER EXPRESS OR 
IMPLIED, INCLUDING WARRANTIES OF FITNESS, MERCHANTABILITY, AND FREEDOM FROM 
PATENT OR COPYRIGHT INFRINGEMENT ARE HEREBY DISCLAIMED TO THE FULLEST EXTENT 
SUCH MAY BE DISCLAIMED BY LAW.  NO PERSON, INCLUDING ANY DEALER, AGENT OR 
REPRESENTATIVE OF I/O, IS AUTHORIZED TO PROVIDE ANY ADDITIONAL WARRANTY ON 
BEHALF OF I/O.

ITEMS NOT COVERED BY THIS WARRANTY.

This Warranty does not cover: (1) conditions resulting from customer damage 
such as misuse, abuse, neglect, accident, alteration or use in any manner 
contrary to instructions provided by I/O; (2) damage caused by acts of God or 
nature; (3) damage resulting from alteration, repair or attempted repair by 
individuals other than I/O employees or I/O designated authorized 
representatives; (4) conditions resulting from normal wear and tear; (5) 
failure to perform proper routine maintenance; (6) continued use of the 
Product after partial failure of any item; (7) items that have been used with 
an improper accessory; or (8) damage caused during shipment unless I/O 
expressly agrees in writing, in advance of shipment, to assume the risks of 
damage caused during shipment.  With regard to any Air Gun manufactured by 
I/O, this Warranty applies only to the metal components of such Air Gun and 
shall not, under any circumstance, apply to any other parts or components of 
the Air Gun.

This Warranty applies to I/O Products only.  I/O may also provide to a 
Purchaser certain products which are manufactured by other companies.  I/O 
MAKES NO REPRESENTATIONS REGARDING THE EXTENT, AVAILABILITY OR APPLICABILITY 
OF WARRANTIES PROVIDED BY OUTSIDE MANUFACTURERS.  Therefore, Purchaser may 
wish to consult such outside manufacturers directly to determine the extent, 
availability and/or applicability of these warranties, if any.

RESTRICTIONS ON USE.

Purchaser may install, use and execute only one (1) copy of the I/O Software 
for use on only one (1) computer at a time.  I/O Software may not be copied, 
distributed, republished, uploaded, posted, decompiled, disassembled, 
modified or transmitted in any way without I/O's prior written consent.  I/O 
Software is licensed on a non-exclusive basis solely for Purchaser's use.  
Embedded software organic to and contained in I/O Products is to be used by 
Purchaser solely within the Product in which such I/O Software resides when 
shipped.  ANY VIOLATION OF THIS PROVISION VOIDS ALL WARRANTIES AS TO SUCH 
PRODUCTS.


<PAGE>

I/O's Products may not be copied or reverse-engineered in any way without 
I/O's prior written consent.  In addition, I/O Products may only be repaired 
or modified by I/O or by an authorized I/O representative, except as 
otherwise directed in writing by I/O.  ANY VIOLATION OF THIS PROVISION VOIDS 
ALL WARRANTIES AS TO SUCH PRODUCTS.

STATE AND FOREIGN LAW RIGHTS.

Some states and non-U.S. jurisdictions do not permit the exclusion or 
limitation of incidental or consequential damages, or limitations on how long 
an implied warranty may last.  Therefore, the above limitations or exclusions 
may not apply to all Purchasers.  This Warranty gives Purchasers specific 
legal rights, and certain Purchasers may also have other rights which vary 
from state to state, or country to country.

Purchaser agrees that I/O's total liability under this agreement for all 
causes of action, whether in contract or in tort, shall be limited to a 
maximum amount equal to the purchase price Purchaser paid for the Product.  
Purchaser agrees that the internal laws, and not the choice of laws, of Texas 
shall apply to this Warranty.

SEVERABILITY.

If any one or more of the paragraphs or parts of this Warranty shall be 
determined to be invalid, illegal or unenforceable in any respect, it is the 
intent of both parties that the validity, legality and enforceability of the 
remaining paragraphs and parts contained herein shall not in any way be 
affected or impaired thereby, and that such invalid, illegal or unenforceable 
paragraph(s) or part(s) be reformed in a manner consistent with the parties' 
contractual intent so as to comply with applicable law.

WARRANTY PROCEDURE.

A Purchaser needing to take advantage of this Warranty should advise I/O in 
writing immediately.  Write to:

     Input/Output, Inc.
     Attention: Warranty Claims
     11104 W. Airport Blvd., Suite 200
     Stafford, Texas 77477

     Or by facsimile: (281) 552-3388

A Purchaser seeking warranty services must, as directed by I/O, ship the 
Product to I/O, or to I/O's designated representative, along with a detailed 
description of the problem(s) Purchaser has encountered with the Product(s) 
and a return shipping address.  Purchaser shall be responsible for any 
freight charge associated with delivering the Product to I/O or its 
designated representative; if such freight charges are not paid by Purchaser, 
I/O shall bill Purchaser for any such fees incurred by I/O.  

In the event that I/O determines that the Product is defective, I/O shall pay 
any freight charges associated with returning the repaired, adjusted or 
replaced Product to Purchaser.  In addition, Purchaser shall be responsible 
for any travel expenses incurred by I/O to satisfy the terms of this Warranty 
at Purchaser's place of business or other site as requested by Purchaser. 
COMPLYING WITH THESE WARRANTY

<PAGE>

PROCEDURES IS A CONDITION PRECEDENT TO I/O'S OBLIGATIONS UNDER THIS 
WARRANTY.  I/O RESERVES THE RIGHT TO DETERMINE WHETHER THIS WARRANTY SHALL 
COVER ANY REPAIRS, ADJUSTMENTS OR REPLACEMENTS REQUESTED BY THE PURCHASER. 

<PAGE>

                                     ADDENDUM A

                             Geophones and Hydrophones


     SPECIFIED PRODUCT                            WARRANTY PERIOD 
     -----------------                            --------------- 

     1.   Cases and Plastic Parts                 1.5 Years
     2.   Geophone Elements:
             SM-24                                Three Years
             SM-4                                 Three Years
             SM-4 LD                              Three Years
             SM-4 HS                              Three Years
             SM-4m                                Two Years
             SM-6                                 Two Years
             SM-7                                 Two Years
             SM-7m                                Two Years
             SM-9                                 Two Years
             SM-11                                Two Years
             SM-15                                Two Years
             SM-4 HT                              30 Days
             SM-6 HT                              30 Days
     3.   Testers                                 180 Days
     4.   Connectors                              90 Days
     5.   Hydrophones                             90 Days
     6.   Ocean Bottom Sensor                     30 Days

<PAGE>

                                     SCHEDULE 1

                                  RENTAL INVENTORY
<TABLE>
-----------------------------------------------------------------------------  
PART NUMBER    DESCRIPTION                                           QUANTITY
-----------------------------------------------------------------------------  
<S>            <C>                                                   <C>
1380000001     MRX Remote Units                                         711
1390000963     RSR-3 Remote Units                                       197
1385000001     BCX Module                                               300
136200         RSX Remote Units                                          72
13200          RSC Remote Units                                         319
136100         ALX                                                       51
1361500001     ALX Battery Converter                                     55
1381710001     RSC Battery Packs                                        405
1381710002     Solar Battery Packs                                      343
1338002200     Line Interface Module (LIM)                                6
1348002200     System Control Module (SCM)                                3
1312002201     Operator Console Module (OCM)                              3
1388000001     Marine Line Controller (MPC-1)                             1
232100         Oscilloscope                                               1
1090250005     Seismic Source Synchronizer Decoder Model DEC-301          5
1091500005     SSS Encoder 301                                            1
229081         Radio Maxtrac (Motorola)                                   4
CA-2417-18     ALX/ALX Cables                                             6
CA-2174        ALX/Near MRX Cables                                       11
1358700112     Microwave Link Set                                         1
145062         Sentry System                                              1
               SM 4HS Geophones (6 per), CL 1000, MP16                1,974
               SM 24 Geophones (6 per) AE-8, MP16                     2,473
               SM 24 Geophone (6 per) CL-100, MP16                    1,597
               SM 4 Geophones (9 per) CL 100, MP16                    2,171
               3C singles, 10 Hz                                        378
               SM-24, 6 per, PE-3, MP16                               2,400
CA-2255        MRX Cables 450 meter                                      18
CA-2450        BCX Cables 3 T.O. 30 meter                                60
7205895003     Sleeve Guns-10 CID                                         3
0700007B5070   Sleeve Gun-70 CID                                          8
0700007B5100   Sleeve Guns-100 CID                                        2
0700007B5150   Sleeve Guns-150 CID                                        2
1443000002     3490 Tape Transport Module                                 2
1376500001     Correlator (CSX)                                           1
1350003036     Correlator (CSM)                                           1
1346140001     Power Supply                                               4
1375100001     Battery Charger                                            1 
-----------------------------------------------------------------------------  
</TABLE>

<PAGE>

                                     SCHEDULE 2
                            LEASES AND LEASED INVENTORY

<TABLE>
-------------------------------------------------------------------------------------------------------- 
  Lease
  Number     Date of Lease              Customer                          Description of Equipment
-------------------------------------------------------------------------------------------------------- 
 <S>         <C>               <C>                                   <C>
 R9804010      5/26/98         Acadian Geophysical Svcs., Inc.       4 SSS Decoder Model 301 W/Backpack  
-------------------------------------------------------------------------------------------------------- 
 R9804090      5/26/98         Acadian Geophysical Svcs., Inc.       4 Radio Max Trac 300
-------------------------------------------------------------------------------------------------------- 
 R9712111      12/22/97        Datum Exploration, Ltd.               50 MRX-1 Remote Units
                                                                     100 Solar Battery Packs (SBP)
-------------------------------------------------------------------------------------------------------- 
 R9801090      00/05/98        Mitcham Industries                    3 Gun SG-1, 10 CID (No Hangers)
-------------------------------------------------------------------------------------------------------- 
 R9804210      5/26/98         Paragon Geophysical Services, Inc.    40 MRX-1 Remote Units
                                                                     40 Solar Battery Packs
-------------------------------------------------------------------------------------------------------- 
 R9610170      10/17/96        Suelopetrol, C.A.                     4 Advance Line Tap (ALX) 
                                                                     4 ALX Down Converters
                                                                     4 Solar Battery Pack (SBP)
                                                                     6 ALX/ALX (400 Meter) Cables
-------------------------------------------------------------------------------------------------------- 
 R9805200      5/20/98         Universal Seismic Associates          600 SM-24 Land Strings, 3S/2P
-------------------------------------------------------------------------------------------------------- 
 R9705220      5/22/97         Veritas DGC Land, Inc., Suc., Arg.    50 MRX-1 Remote Units
                                                                     50 Solar Battery Packs (SBP)
-------------------------------------------------------------------------------------------------------- 
 R9705300      8/12/97         Veritas DGC Land, Inc.                193 MRX-1 Remote Units
                                                                     35 ALX's
                                                                     1 Sentry System
                                                                     1 CSX 
                                                                     2 Line Interface Module
-------------------------------------------------------------------------------------------------------- 
 R9804300      4/30/98         Veritas DGC Land, Inc.                137 RSR-3 Remote Units
-------------------------------------------------------------------------------------------------------- 
 R9706100      8/12/97         Veritas DGC Land, Inc.                82 MRX-1 Remote Units
                                                                     2 ALX
                                                                     1 Operator Control Module (OCM)
                                                                     1 System Control Module (SCM)
                                                                     1 Tape Transport Module (TTM)
                                                                     1 Line Interface Module (LIM
-------------------------------------------------------------------------------------------------------- 
 R9707240      9/30/97         Veritas DGC Land, Inc.(Ecuador)       50 MRX-1 Remote Units
-------------------------------------------------------------------------------------------------------- 
 R9711250      8/20/98         Veritas DGC Land, Inc.                2400 Strings of 6 SM-24 Geophones
-------------------------------------------------------------------------------------------------------- 
 R9805010      5/8/98          Western Geophysical                   1 Operator Control Modules(OCM)
                                                                     1 System Control Module (SCM)
                                                                     1 Line Interface Module (LIM)
                                                                     1 Power Supply
                                                                     8 MRX-1 Remote Units
                                                                     24 Solar Battery Packs
                                                                     4 Advanced Line Tap (ALX)
                                                                     4 ALX Battery Converters
                                                                     1 Battery Charger
                                                                     4 MRX/MRX Cables
-------------------------------------------------------------------------------------------------------- 

<PAGE>
-------------------------------------------------------------------------------------------------------- 
                                                                     3 ALX/ALX Cables
                                                                     4 ALX/Near MRX Cables
-------------------------------------------------------------------------------------------------------- 
 R9804030        5/1/98        Western Geophysical Company           2 Gun SG-IIB, 150 CID
                                                                     2 Gun SG-IIB, 100 CID
-------------------------------------------------------------------------------------------------------- 
</TABLE>

<PAGE>

                                     SCHEDULE 3
                     ADDITIONAL LEASES AND ADDITIONAL INVENTORY


<TABLE>
------------------------------------------------------------------------------------------------------------- 
  Lease
  Number     Date of Lease              Customer                          Description of Equipment
------------------------------------------------------------------------------------------------------------- 
 <S>         <C>               <C>                            <C>
 R9803220      3/22/98         Grant Geophysical              1 CNE Board 
------------------------------------------------------------------------------------------------------------- 
 R980504       5/29/98         Kaliningradgeofizika           1-540 Channel RSR-3 Seismic Recording System 
------------------------------------------------------------------------------------------------------------- 
 R01340        4/14/98         PGS Onshore                    1 Wire Wrap Assembly
------------------------------------------------------------------------------------------------------------- 
 R980420       4/28/98         Polish Oil and Gas             1 Microwave Link Set
------------------------------------------------------------------------------------------------------------- 
 R9709220      9/23/97         3-D Geophysical                4 CNE Boards
------------------------------------------------------------------------------------------------------------- 
 R00860        4/19/97         Veritas DGC Land, Inc.         2 DCU to RSR-3 Cable
------------------------------------------------------------------------------------------------------------- 
 R9707181      7/18/97         Veritas DGC Land, Inc.         1 Tape Transport Model 42 (TTM)
------------------------------------------------------------------------------------------------------------- 
 R9710020      10/4/97         Veritas DGC Land, Inc.         2 Line Interface Modules (LIM)
------------------------------------------------------------------------------------------------------------- 
 R9712081      12/15/97        Veritas DGC Land, Inc.         106 MRX-1 Remote Units
------------------------------------------------------------------------------------------------------------- 
 R9802770      3/10/97         Veritas DGC Land, Inc.         1 Line Interface Module (LIM)
------------------------------------------------------------------------------------------------------------- 
 R9801071      1/7/98          Veritas DGC Land, Inc.         1 QCR System
------------------------------------------------------------------------------------------------------------- 
 R01339        3/20/98         Veritas DGC Land, Inc.         1 Fujitsu Tape Drive
------------------------------------------------------------------------------------------------------------- 
 R9804230      4/23/98         Veritas DGC Land, Inc.         22 RSR-3 Remote Units
                                                              22 Solar Battery Packs
------------------------------------------------------------------------------------------------------------- 
 R9805140      5/11/98         Veritas DGC Land, Inc.         185 MRX-1 Remote Units
                                                              295 Solar Battery Packs
                                                              4 Battery Chargers
------------------------------------------------------------------------------------------------------------- 
 R00861        5/29/97         Veritas DGC Land, Inc.         1 DPM PC Assy
------------------------------------------------------------------------------------------------------------- 
 R9801070      1/8/98          Western Geophysical Company    1 QCR System
------------------------------------------------------------------------------------------------------------- 
 R9803270      3/27/98         Western Geophysical Company    2 Microwave Link Sets
------------------------------------------------------------------------------------------------------------- 
</TABLE>