BANK OF AMERICA
                                                                   BUSINESS LOAN
                                                             CONTINUING GUARANTY

In this guaranty (the "Guaranty"), "Guarantor", refers to each business
organization or person who signs below. "Bank" refers to Bank of America Texas,
N.A.

1. GUARANTY In consideration of the financial arrangements between Bank and the
Borrowers listed below (each a "Borrower" and collectively, the "Borrowers"),
Guarantor guarantees payment of, and agrees to pay to the order of Bank on
demand, the debts (herein so called) to the Bank of the following Borrower(s):

1.    Oyo Geospace Corporation, Borrower
2.
3.
4.

If two or more Borrowers are named above, the Guarantor guarantees payment of
any Debt they incur together as well as any Debt each one incurs alone. The Debt
includes all loans and advances made by Bank to Borrower and all other
obligations and liabilities of Borrower to Bank, whether now existing or
hereafter incurred or created, whether voluntary or involuntary, whether
individually or with others, whether due or not due, whether absolute or
contingent, whether liquidated or unliquidated or for a determined or
undetermined amount with respect to that certain Business Loan Agreement between
Borrower and Bank dated of even date herewith.

The Debt also includes any and all renewals, extensions, modifications and
increases of each Borrower's obligations to Bank.

Guarantor irrevocably and unconditionally covenants and agrees that it is liable
for the Debt as primary obligor.

Guarantor represents and warrants that it has received or will receive direct or
indirect benefit from the making of this Guaranty and the loans made by Bank to
Borrower, that Guarantor is familiar with the financial condition of Borrower
and the value of any collateral security for the Debt, and that Bank has made no
representations to Guarantor to induce Guarantor to execute this Guaranty.

This Guaranty is continuous. Until revoked, it covers Debts Borrower incurs even
after fully repaying any previous Debts. Each guarantor's obligations remain and
will not be affected in the event of revocation by any other guarantor.

This Guaranty is unconditional. Bank may require Guarantor to pay, and Guarantor
shall not be released or discharged, even if Bank does not:

o    proceed against any borrower, guarantor, or other party; 
o    perfect any security interest; 
o    proceed against any security; or 
o    pursue any other remedy.

Bank may do any of the following without release or discharging Guarantor;

o     release, in full or in part, Borrower, other guarantors, or any other
      obligors from liability with respect to the Debt; 
o     grant any forbearance or compromise to Borrower; 
o     release, subordinate its interest in, surrender, or otherwise impair the 
      value of, its interest in any collateral securing the Debt; or 
o     fail to exercise diligence, commercial reasonableness, or reasonable care
      in the preservation, enforcement or sale of any collateral securing the 
      Debt.

                                                                               1

<PAGE>

Bank may require Guarantor to pay even if a statute of limitations or disability
bars recovery from Borrower, or the Debt is or becomes otherwise unenforceable.

Guarantor waives the benefit of any statute of limitations that would apply to
this Guaranty.

Guarantor hereby waives all notices, including, without limitation, notice of

(a)   acceptance of this Guaranty,
(b)   the extension of credit by Bank to Borrower,
(c) the occurrence of any breach or default by Borrower in respect of the Debt,
(d) the sale or foreclosure of any collateral for the Debt, 
(e) the transfer of the Debt to any third party, 
(f) intent to accelerate, and 
(g) acceleration.

Guarantor's obligations are independent of Borrower's obligations, and Bank may
sue Guarantor without suing Borrower.

2. LIMITS OF THE GUARANTY Guarantor shall not be liable for any amount over the
following limit, although Bank may allow the Debt to go above it:

      the principal amount of $10,000,000.00; plus
      any interest, fees, and other expenses arising out of, or constituting 
      part of, the Debt.

This Guaranty is in addition to any other guaranty given by Guarantor.

3.    RIGHTS OF THE BANK Bank may from time to time, without notice to or demand
      on Guarantor:

o     change the interest rate on or renew the Debt;
o     accelerate, extend, compromise, or otherwise change the repayment period
      of the Debt; 
o     receive, substitute, or release collateral for the Debt;
o     sell, otherwise dispose of, or apply collateral in any order; 
o     apply amounts received from anyone other than Guarantor to any 
      unguaranteed part of the Debt; 
o     assign or sell the whole or a portion of the Debt and this Guaranty; or 
o     foreclose any deed of trust securing the Debt, either by judicial 
      foreclosure or power of sale. Even if the foreclosure destroys or
      lessens Guarantor's rights against Borrower, the Guarantor will be liable
      to Bank for any part of the Debt remaining unpaid after foreclosure.

Bank may, at its option, request periodic financial statements from Guarantor.
Guarantor agrees to supply these statements promptly whenever they are
requested.

Bank may exercise these rights either before or after Guarantor revokes this
Guaranty, and without affecting any obligation under this Guaranty.

Bank may assign this Guaranty, in whole or part, without notice, and Bank and
any assignee or purchaser, or any prospective assignee or purchaser of the Debt,
may exchange financial information about Guarantor with each other in connection
with any assignment or purchase transaction.

If a Borrower is a corporation or partnership, Bank is not required to
investigate the powers of anyone acting on Borrower's behalf.

                                                                               2
<PAGE>

4. PROTECTING THE BANK'S INTEREST Guarantor agrees that any amounts Borrower
owes Guarantor now or in the future are subordinated to Borrower's debt to Bank.
If Bank requires, Guarantor, as a trustee for the Bank, shall collect amounts
Borrower owes Guarantor and pay them to Bank in reduction of the Debt without
affecting or reducing any obligations under this Guaranty.

Guarantor agrees that Guarantor does not have, and hereby waives, any:

o     right of subrogation, reimbursement, indemnification or contribution
      arising from the existence or performance of this Guaranty. This includes
      any such rights arising from contract, statutory law or otherwise, and
      includes any claim of subrogation under the Bankruptcy Code (Title 11 of
      the U.S. Code) or any successor statute; 
o     right to enforce a remedy which Bank now has or may later have against 
      Borrower; 
o     right to participate in security now or later held by Bank; or 
o     right to any defense based on a claim that the obligations under this 
      Guaranty are more burdensome or are in excess of Borrower's debt to Bank

Guarantor is solely responsible for obtaining any financial information from
Borrower that guarantor may require. Bank is not required to give Guarantor any
information about Borrower's business operations or financial condition, or any
other notices or demands of any kind, including notices of new debts that may be
incurred by Borrower, notices of default or notice of acceptance of this
Guaranty.

5. SECURITY AND RIGHT OF SETOFF To secure all the Debts covered by this
Guaranty, Guarantor assigns and grants to Bank a security interest in all of
Guarantor's:

o     money;
o     securities;
o     deposit accounts and their proceeds; and
o     any other property maintained in the possession of Bank.

If Borrower defaults, or if any of Guarantor's obligations to Bank are not
fulfilled, Bank may immediately set off any money or proceeds of Guarantor's
deposit accounts, securities, or other property in Bank's possession against the
outstanding Debt.

Bank may also foreclose on any other collateral as provided in the Texas Uniform
Commercial Code and in any security agreements between Bank and Guarantor.

If this Guaranty is secured by real property, Guarantor agrees that any
transfer, assignment, sale or conveyance of such property shall constitute a
default under this Guaranty.

6.    ARBITRATION
(a)   This paragraph concerns the resolution of any controversies or claims
      between Borrower and Bank, including but not limited to those that rise
      from:

      (i)   This Guaranty (including  any renewals, extensions or modifications
            of this Guaranty);
      (ii)  Any document, agreement or procedure related to or delivered in
            connection with this Guaranty;
      (iii) Any violation of this Guaranty; or
      (iv)  Any claims for damages resulting from any business conducted between
            Guarantor and Bank, including claims for injury to persons, property
            or business interests (torts).

(b)   At the request of Guarantor or Bank, any such controversies or claims will
      be settled by arbitration in accordance with the United States Arbitration
      Act. THE UNITED STATES ARBITRATION ACT WILL APPLY EVEN THOUGH THIS
      AGREEMENT PROVIDES THAT IT IS GOVERNED BY TEXAS LAW.
(c)   Arbitration proceedings will be administered by the American Arbitration
      Association and will be subject to its commercial rules of arbitration.
(d)   For purposes of the application of the statute of limitation, the filing
      of a lawsuit, and any claim or controversy which may be arbitrated under
      this paragraph is subject to any applicable statute of limitations. The
      arbitrators will have the authority to decide whether any such claim or
      controversy is barred by the statute of limitations and, if so, to dismiss
      the arbitration on that basis.

                                                                               3

<PAGE>

(e)   If there is a dispute as to whether an issue is arbitrable, the
      arbitrators will have the authority to resolve any such dispute.
(f)   The decision that results from an arbitration proceeding may be submitted
      to any authorized court of law to be confirmed and enforced.
(g) This provision does not limit the right of Guarantor or Bank to:

      (i)   exercise self-help remedies such as setoff;
      (ii)  foreclose against or sell any real or personal property collateral;
      (iii) act in a court of law, before, during or after the arbitration
            proceeding to obtain:

            (A) a provisional or interim remedy; and/or 
            (B) additional or supplementary remedies

(h)   The pursuit of a successful action for provisional, interim, additional or
      supplementary remedies, or the filing of a court action, does not
      constitute a waiver of the right of Guarantor or Bank, including the suing
      party, to submit the controversy or claim to arbitration if the other
      party contests the lawsuit.

7. EXPENSES Guarantor agrees to pay all reasonable attorneys' fees, including
allocated costs of the Bank's in-house counsel, court costs and all other
expenses Bank incurs in enforcing this Guaranty.

8. REVOKING THE GUARANTY Guarantor may revoke this Guaranty as to future
transactions at any time, provided that Guarantor renounces any consideration
given in return for the guaranty of such transactions. Guarantor is obligated on
all credit extended by Bank to Borrower until Bank receives a written notice at
the address shown below revoking this Guaranty.

Any revocation will not affect the Guarantor's obligation for any transactions
that preceded receipt of the written notice, and the Guarantor shall remain
obligated on all debts related to such transactions, even if such debts, before
or after the revocation, have been renewed or modified or any of their terms
shall have been changed in any way.

If this Guaranty is revoked, cancelled or returned, and Bank later must refund
or rescind a payment, or transfer an interest in property back to Borrower, this
Guaranty shall be reinstated as to such payment or interest.

9. ENFORCING THIS GUARANTY THIS GUARANTY IS GOVERNED BY TEXAS LAW, AND BANK MAY
SUE GUARANTOR IN COURTS IN DALLAS COUNTY, TEXAS.

Bank may delay or waive exercising or enforcing any of its rights, including,
without limitation, its rights to setoff and lien, without losing them. Such
rights continue until Bank waives them in writing.

                                                                               4
<PAGE>

10. SIGNATURES/DATE All guarantors who sign are jointly and severally liable for
all obligations under this Guaranty.


This Guaranty is executed as of June ______________________, 1998.

                                                                               5
GEO SPACE CORPORATION, GUARANTOR

Dated:  ___________________


X________________________________
Thomas T. McEntire, Chief Financial Officer


7334 North Gessner Road
Houston, Texas  77040
Tax I.D. No.: 76-0394288

Address for notices to the Bank:

BANK OF AMERICA TEXAS, N.A.
Houston Commercial Lending, #2552
333 Clay Street, Ste. 3600
Houston, Texas  77002

<PAGE>
BANK OF AMERICA
                                                                   BUSINESS LOAN
                                                             CONTINUING GUARANTY

In this guaranty (the "Guaranty"), "Guarantor", refers to each business
organization or person who signs below. "Bank" refers to Bank of America Texas,
N.A.

1. GUARANTY In consideration of the financial arrangements between Bank and the
Borrowers listed below (each a "Borrower" and collectively, the "Borrowers"),
Guarantor guarantees payment of, and agrees to pay to the order of Bank on
demand, the debts (herein so called) to the Bank of the following Borrower(s):

1.    Oyo Geospace Corporation, Borrower
2.
3.
4.

If two or more Borrowers are named above, the Guarantor guarantees payment of
any Debt they incur together as well as any Debt each one incurs alone. The Debt
includes all loans and advances made by Bank to Borrower and all other
obligations and liabilities of Borrower to Bank, whether now existing or
hereafter incurred or created, whether voluntary or involuntary, whether
individually or with others, whether due or not due, whether absolute or
contingent, whether liquidated or unliquidated or for a determined or
undetermined amount with respect to that certain Business Loan Agreement between
Borrower and Bank dated of even date herewith.

The Debt also includes any and all renewals, extensions, modifications and
increases of each Borrower's obligations to Bank.

Guarantor irrevocably and unconditionally covenants and agrees that it is liable
for the Debt as primary obligor.

Guarantor represents and warrants that it has received or will receive direct or
indirect benefit from the making of this Guaranty and the loans made by Bank to
Borrower, that Guarantor is familiar with the financial condition of Borrower
and the value of any collateral security for the Debt, and that Bank has made no
representations to Guarantor to induce Guarantor to execute this Guaranty.

This Guaranty is continuous. Until revoked, it covers Debts Borrower incurs even
after fully repaying any previous Debts. Each guarantor's obligations remain and
will not be affected in the event of revocation by any other guarantor.

This Guaranty is unconditional. Bank may require Guarantor to pay, and Guarantor
shall not be released or discharged, even if Bank does not:

o     proceed against any borrower, guarantor, or other party;
o     perfect any security interest;
      proceed against any security; or
o     pursue any other remedy.

Bank may do any of the following without release or discharging Guarantor;

o     release, in full or in part, Borrower,  other guarantors,  or any other 
      obligors from liability with respect to the Debt;
o     grant any forbearance or compromise to Borrower;
o     release, subordinate its interest in, surrender, or otherwise impair the 
      value of, its interest in any collateral securing the Debt; or
o     fail to exercise diligence, commercial reasonableness, or reasonable care
      in the preservation, enforcement or sale of any collateral securing the
      Debt.

                                                                               1

<PAGE>

Bank may require Guarantor to pay even if a statute of limitations or disability
bars recovery from Borrower, or the Debt is or becomes otherwise unenforceable.

Guarantor waives the benefit of any statute of limitations that would apply to
this Guaranty.

Guarantor hereby waives all notices, including, without limitation, notice of

(a)   acceptance of this Guaranty,
(b)   the extension of credit by Bank to Borrower,
(c) the occurrence of any breach or default by Borrower in respect of the Debt,
(d) the sale or foreclosure of any collateral for the Debt, 
(e) the transfer of the Debt to any third party, 
(f) intent to accelerate, and 
(g) acceleration.

Guarantor's obligations are independent of Borrower's obligations, and Bank may
sue Guarantor without suing Borrower.

2. LIMITS OF THE GUARANTY Guarantor shall not be liable for any amount over the
following limit, although Bank may allow the Debt to go above it:

o     the principal amount of $10,000,000.00; plus
o     any interest, fees, and other expenses arising out of, or constituting 
      part of, the Debt.

This Guaranty is in addition to any other guaranty given by Guarantor.

3.    RIGHTS OF THE BANK Bank may from time to time, without notice to or demand
      on Guarantor:

o     change the interest rate on or renew the Debt;
o     accelerate, extend, compromise, or otherwise change the repayment period 
      of the Debt;
o     receive, substitute, or release collateral for the Debt; 
o     sell, otherwise dispose of, or apply collateral in any order; 
o     apply amounts received from anyone other than Guarantor to any 
      unguaranteed part of the Debt;
o     assign or sell the whole or a portion of the Debt and this Guaranty; or
o     foreclose any deed of trust securing the Debt, either by judicial 
      foreclosure or power of sale. Even if the foreclosure destroys or lessens
      Guarantor's rights against Borrower, the Guarantor will be liable to Bank
      for any part of the Debt remaining unpaid after foreclosure.

Bank may, at its option, request periodic financial statements from Guarantor.
Guarantor agrees to supply these statements promptly whenever they are
requested.

Bank may exercise these rights either before or after Guarantor revokes this
Guaranty, and without affecting any obligation under this Guaranty.

Bank may assign this Guaranty, in whole or part, without notice, and Bank and
any assignee or purchaser, or any prospective assignee or purchaser of the Debt,
may exchange financial information about Guarantor with each other in connection
with any assignment or purchase transaction.

If a Borrower is a corporation or partnership, Bank is not required to
investigate the powers of anyone acting on Borrower's behalf.

                                                                               2
<PAGE>

4. PROTECTING THE BANK'S INTEREST Guarantor agrees that any amounts Borrower
owes Guarantor now or in the future are subordinated to Borrower's debt to Bank.
If Bank requires, Guarantor, as a trustee for the Bank, shall collect amounts
Borrower owes Guarantor and pay them to Bank in reduction of the Debt without
affecting or reducing any obligations under this Guaranty.

Guarantor agrees that Guarantor does not have, and hereby waives, any:

o     right of subrogation, reimbursement, indemnification or contribution
      arising from the existence or performance of this Guaranty. This includes
      any such rights arising from contract, statutory law or otherwise, and
      includes any claim of subrogation under the Bankruptcy Code (Title 11 of
      the U.S. Code) or any successor statute;
o     right to enforce a remedy which Bank now has or may later have against
      Borrower;
o     right to participate in security now or later held by Bank; or
o     right to any defense based on a claim that the  obligations under this 
      Guaranty are more burdensome or are in excess of Borrower's debt to Bank

Guarantor is solely responsible for obtaining any financial information from
Borrower that guarantor may require. Bank is not required to give Guarantor any
information about Borrower's business operations or financial condition, or any
other notices or demands of any kind, including notices of new debts that may be
incurred by Borrower, notices of default or notice of acceptance of this
Guaranty.

5. SECURITY AND RIGHT OF SETOFF To secure all the Debts covered by this
Guaranty, Guarantor assigns and grants to Bank a security interest in all of
Guarantor's:

o     money;
o     securities;
o     deposit accounts and their proceeds; and
o     any other property maintained in the possession of Bank.

If Borrower defaults, or if any of Guarantor's obligations to Bank are not
fulfilled, Bank may immediately set off any money or proceeds of Guarantor's
deposit accounts, securities, or other property in Bank's possession against the
outstanding Debt.

Bank may also foreclose on any other collateral as provided in the Texas Uniform
Commercial Code and in any security agreements between Bank and Guarantor.

If this Guaranty is secured by real property, Guarantor agrees that any
transfer, assignment, sale or conveyance of such property shall constitute a
default under this Guaranty.

6.    ARBITRATION
(a)   This paragraph concerns the resolution of any controversies or claims
      between Borrower and Bank, including but not limited to those that rise
      from:

      (i)   This Guaranty (including any renewals, extensions or modifications
            of this Guaranty);
      (ii)  Any document, agreement or procedure related to or delivered in
            connection with this Guaranty;
      (iii) Any violation of this Guaranty; or
      (iv)  Any claims for damages resulting from any business conducted between
            Guarantor and Bank, including claims for injury to persons, property
            or business interests (torts).

(b)   At the request of Guarantor or Bank, any such controversies or claims will
      be settled by arbitration in accordance with the United States Arbitration
      Act. THE UNITED STATES ARBITRATION ACT WILL APPLY EVEN THOUGH THIS
      AGREEMENT PROVIDES THAT IT IS GOVERNED BY TEXAS LAW.
(c)   Arbitration proceedings will be administered by the American Arbitration
      Association and will be subject to its commercial rules of arbitration.
(d)   For purposes of the application of the statute of limitation, the filing
      of a lawsuit, and any claim or controversy which may be arbitrated under
      this paragraph is subject to any applicable statute of limitations. The
      arbitrators will have the authority to decide whether any such claim or
      controversy is barred by the statute of limitations and, if so, to dismiss
      the arbitration on that basis.

                                                                               3

<PAGE>

(e)   If there is a dispute as to whether an issue is arbitrable, the
      arbitrators will have the authority to resolve any such dispute.
(f)   The decision that results from an arbitration proceeding may be submitted
      to any authorized court of law to be confirmed and enforced.
(g)   This provision does not limit the right of Guarantor or Bank to:

      (i)   exercise self-help remedies such as setoff;
      (ii)  foreclose against or sell any real or personal property collateral;
      (iii) act in a court of law, before, during or after the arbitration
            proceeding to obtain:

            (A) a provisional or interim remedy; and/or (B) additional or
            supplementary remedies

(h)   The pursuit of a successful action for provisional, interim, additional or
      supplementary remedies, or the filing of a court action, does not
      constitute a waiver of the right of Guarantor or Bank, including the suing
      party, to submit the controversy or claim to arbitration if the other
      party contests the lawsuit.

7. EXPENSES Guarantor agrees to pay all reasonable attorneys' fees, including
allocated costs of the Bank's in-house counsel, court costs and all other
expenses Bank incurs in enforcing this Guaranty.

8. REVOKING THE GUARANTY Guarantor may revoke this Guaranty as to future
transactions at any time, provided that Guarantor renounces any consideration
given in return for the guaranty of such transactions. Guarantor is obligated on
all credit extended by Bank to Borrower until Bank receives a written notice at
the address shown below revoking this Guaranty.

Any revocation will not affect the Guarantor's obligation for any transactions
that preceded receipt of the written notice, and the Guarantor shall remain
obligated on all debts related to such transactions, even if such debts, before
or after the revocation, have been renewed or modified or any of their terms
shall have been changed in any way.

If this Guaranty is revoked, cancelled or returned, and Bank later must refund
or rescind a payment, or transfer an interest in property back to Borrower, this
Guaranty shall be reinstated as to such payment or interest.

9. ENFORCING THIS GUARANTY THIS GUARANTY IS GOVERNED BY TEXAS LAW, AND BANK MAY
SUE GUARANTOR IN COURTS IN DALLAS COUNTY, TEXAS.

Bank may delay or waive exercising or enforcing any of its rights, including,
without limitation, its rights to setoff and lien, without losing them. Such
rights continue until Bank waives them in writing.

                                                                               4
<PAGE>

10. SIGNATURES/DATE All guarantors who sign are jointly and severally liable for
all obligations under this Guaranty.


This Guaranty is executed as of ____________________, 1998.


GEO SPACE CANADA, INC., GUARANTOR

Dated:  ___________________


X________________________________
Thomas T. McEntire, Chief Financial Officer


2735 - 37th Avenue, N.E.
Calgary, Alberta
Canada T1Y5R8

Tax I.D. No.: not applicable for Canadian entity

Address for notices to the Bank:

BANK OF AMERICA TEXAS, N.A.
Houston Commercial Lending, #2552
333 Clay Street, Ste. 3600
Houston, Texas  77002


<PAGE>
BANK OF AMERICA

                                                                   BUSINESS LOAN
                                                             CONTINUING GUARANTY


In this guaranty (the "Guaranty"), "Guarantor", refers to each business
organization or person who signs below. "Bank" refers to Bank of America Texas,
N.A.

1. GUARANTY In consideration of the financial arrangements between Bank and the
Borrowers listed below (each a "Borrower" and collectively, the "Borrowers"),
Guarantor guarantees payment of, and agrees to pay to the order of Bank on
demand, the debts (herein so called) to the Bank of the following Borrower(s):

1.    Oyo Geospace Corporation, Borrower
2.
3.
4.

If two or more Borrowers are named above, the Guarantor guarantees payment of
any Debt they incur together as well as any Debt each one incurs alone. The Debt
includes all loans and advances made by Bank to Borrower and all other
obligations and liabilities of Borrower to Bank, whether now existing or
hereafter incurred or created, whether voluntary or involuntary, whether
individually or with others, whether due or not due, whether absolute or
contingent, whether liquidated or unliquidated or for a determined or
undetermined amount with respect to that certain Business Loan Agreement between
Borrower and Bank dated of even date herewith.

The Debt also includes any and all renewals, extensions, modifications and
increases of each Borrower's obligations to Bank.

Guarantor irrevocably and unconditionally covenants and agrees that it is liable
for the Debt as primary obligor.

Guarantor represents and warrants that it has received or will receive direct or
indirect benefit from the making of this Guaranty and the loans made by Bank to
Borrower, that Guarantor is familiar with the financial condition of Borrower
and the value of any collateral security for the Debt, and that Bank has made no
representations to Guarantor to induce Guarantor to execute this Guaranty.

This Guaranty is continuous. Until revoked, it covers Debts Borrower incurs even
after fully repaying any previous Debts. Each guarantor's obligations remain and
will not be affected in the event of revocation by any other guarantor.

This Guaranty is unconditional. Bank may require Guarantor to pay, and Guarantor
shall not be released or discharged, even if Bank does not:

o     proceed against any borrower, guarantor, or other party;
o     perfect any security interest;
o     proceed against any security; or
o     pursue any other remedy.

Bank may do any of the following without release or discharging Guarantor;

o     release, in full or in part, Borrower, other guarantors, or any other 
      obligors from liability with respect to the Debt;
o     grant any forbearance or compromise to Borrower;
o     release, subordinate its interest in, surrender, or otherwise impair 
      the value of, its interest in any collateral securing the Debt; or
o     fail to exercise diligence, commercial reasonableness, or reasonable care
      in the preservation, enforcement or sale of any collateral securing the
      Debt.

Bank may require Guarantor to pay even if a statute of limitations or disability
bars recovery from Borrower, or the Debt is or becomes otherwise unenforceable.

                                                                               1

<PAGE>

Guarantor waives the benefit of any statute of limitations that would apply to
this Guaranty.

Guarantor hereby waives all notices, including, without limitation, notice of

(a) acceptance of this Guaranty,
(b) the extension of credit by Bank to Borrower,
(c) the occurrence of any breach or default by Borrower in respect of the Debt,
(d) the sale or foreclosure of any collateral for the Debt, 
(e) the transfer of the Debt to any third party, 
(f) intent to accelerate, and 
(g) acceleration.

Guarantor's obligations are independent of Borrower's obligations, and Bank may
sue Guarantor without suing Borrower.

2. LIMITS OF THE GUARANTY Guarantor shall not be liable for any amount over the
following limit, although Bank may allow the Debt to go above it:

o     the principal amount of $10,000,000.00; plus
o     any interest, fees, and other expenses arising out of, or constituting 
      part of, the Debt.

This Guaranty is in addition to any other guaranty given by Guarantor.

3.    RIGHTS OF THE BANK Bank may from time to time, without notice to or demand
      on Guarantor:

o     change the interest rate on or renew the Debt;
o     accelerate, extend, compromise, or otherwise change the repayment period 
      of the Debt;
o     receive, substitute, or release collateral for the Debt; 
o     sell, otherwise dispose of, or apply collateral in any order; 
o     apply amounts received from anyone other than Guarantor to any 
      unguaranteed part of the Debt;
o     assign or sell the whole or a portion of the Debt and this Guaranty; or
o     foreclose any deed of trust securing the Debt, either by judicial 
      foreclosure or power of sale. Even if the foreclosure destroys or lessens 
      Guarantor's rights against Borrower, the Guarantor will be liable to Bank
      for any part of the Debt remaining unpaid after foreclosure.

Bank may, at its option, request periodic financial statements from Guarantor.
Guarantor agrees to supply these statements promptly whenever they are
requested.

Bank may exercise these rights either before or after Guarantor revokes this
Guaranty, and without affecting any obligation under this Guaranty.

Bank may assign this Guaranty, in whole or part, without notice, and Bank and
any assignee or purchaser, or any prospective assignee or purchaser of the Debt,
may exchange financial information about Guarantor with each other in connection
with any assignment or purchase transaction.

If a Borrower is a corporation or partnership, Bank is not required to
investigate the powers of anyone acting on Borrower's behalf.

4. PROTECTING THE BANK'S INTEREST Guarantor agrees that any amounts Borrower
owes Guarantor now or in the future are subordinated to Borrower's debt to Bank.
If Bank requires, Guarantor, as a trustee for the Bank, shall collect amounts
Borrower owes Guarantor and pay them to Bank in reduction of the Debt without
affecting or reducing any obligations under this Guaranty.

Guarantor agrees that Guarantor does not have, and hereby waives, any:

                                                                               2

<PAGE>

o     right of subrogation, reimbursement, indemnification or contribution
      arising from the existence or performance of this Guaranty. This includes
      any such rights arising from contract, statutory law or otherwise, and
      includes any claim of subrogation under the Bankruptcy Code (Title 11 of
      the U.S. Code) or any successor statute;
o     right to enforce a remedy which Bank now has or may later have against
      Borrower;
o     right to participate in security now or later held by Bank; or
o     right to any defense based on a claim that the obligations under this 
      Guaranty are more burdensome or are in excess of Borrower's debt to Bank

Guarantor is solely responsible for obtaining any financial information from
Borrower that guarantor may require. Bank is not required to give Guarantor any
information about Borrower's business operations or financial condition, or any
other notices or demands of any kind, including notices of new debts that may be
incurred by Borrower, notices of default or notice of acceptance of this
Guaranty.

5. SECURITY AND RIGHT OF SETOFF To secure all the Debts covered by this
Guaranty, Guarantor assigns and grants to Bank a security interest in all of
Guarantor's:

o     money;
o     securities;
o     deposit accounts and their proceeds; and
o     any other property maintained in the possession of Bank.

If Borrower defaults, or if any of Guarantor's obligations to Bank are not
fulfilled, Bank may immediately set off any money or proceeds of Guarantor's
deposit accounts, securities, or other property in Bank's possession against the
outstanding Debt.

Bank may also foreclose on any other collateral as provided in the Texas Uniform
Commercial Code and in any security agreements between Bank and Guarantor.

If this Guaranty is secured by real property, Guarantor agrees that any
transfer, assignment, sale or conveyance of such property shall constitute a
default under this Guaranty.

6.    ARBITRATION
(a)   This paragraph concerns the resolution of any controversies or claims
      between Borrower and Bank, including but not limited to those that rise
      from:

      (i)   This Guaranty (including any renewals, extensions or modifications
            of this Guaranty);
      (ii)  Any document, agreement or procedure related to or delivered in
            connection with this Guaranty;
      (iii) Any violation of this Guaranty; or
      (iv)  Any claims for damages resulting from any business conducted between
            Guarantor and Bank, including claims for injury to persons, property
            or business interests (torts).

(b)   At the request of Guarantor or Bank, any such controversies or claims will
      be settled by arbitration in accordance with the United States Arbitration
      Act. THE UNITED STATES ARBITRATION ACT WILL APPLY EVEN THOUGH THIS
      AGREEMENT PROVIDES THAT IT IS GOVERNED BY TEXAS LAW.
(c)   Arbitration proceedings will be administered by the American Arbitration
      Association and will be subject to its commercial rules of arbitration.
(d)   For purposes of the application of the statute of limitation, the filing
      of a lawsuit, and any claim or controversy which may be arbitrated under
      this paragraph is subject to any applicable statute of limitations. The
      arbitrators will have the authority to decide whether any such claim or
      controversy is barred by the statute of limitations and, if so, to dismiss
      the arbitration on that basis.
(e)   If there is a dispute as to whether an issue is arbitrable, the
      arbitrators will have the authority to resolve any such dispute.
(f)   The decision that results from an arbitration proceeding may be submitted
      to any authorized court of law to be confirmed and enforced.
(g)   This provision does not limit the right of Guarantor or Bank to:

                                                                               4

<PAGE>

      (i)   exercise self-help remedies such as setoff;
      (ii)  foreclose against or sell any real or personal property collateral;
      (iii) act in a court of law, before, during or after the arbitration
                  proceeding to obtain:

            (A) a provisional or interim remedy; and/or (B) additional or
            supplementary remedies

(h)   The pursuit of a successful action for provisional, interim, additional or
      supplementary remedies, or the filing of a court action, does not
      constitute a waiver of the right of Guarantor or Bank, including the suing
      party, to submit the controversy or claim to arbitration if the other
      party contests the lawsuit.

7. EXPENSES Guarantor agrees to pay all reasonable attorneys' fees, including
allocated costs of the Bank's in-house counsel, court costs and all other
expenses Bank incurs in enforcing this Guaranty.

8. REVOKING THE GUARANTY Guarantor may revoke this Guaranty as to future
transactions at any time, provided that Guarantor renounces any consideration
given in return for the guaranty of such transactions. Guarantor is obligated on
all credit extended by Bank to Borrower until Bank receives a written notice at
the address shown below revoking this Guaranty.

Any revocation will not affect the Guarantor's obligation for any transactions
that preceded receipt of the written notice, and the Guarantor shall remain
obligated on all debts related to such transactions, even if such debts, before
or after the revocation, have been renewed or modified or any of their terms
shall have been changed in any way.

If this Guaranty is revoked, cancelled or returned, and Bank later must refund
or rescind a payment, or transfer an interest in property back to Borrower, this
Guaranty shall be reinstated as to such payment or interest.

9. ENFORCING THIS GUARANTY THIS GUARANTY IS GOVERNED BY TEXAS LAW, AND BANK MAY
SUE GUARANTOR IN COURTS IN DALLAS COUNTY, TEXAS.

Bank may delay or waive exercising or enforcing any of its rights, including,
without limitation, its rights to setoff and lien, without losing them. Such
rights continue until Bank waives them in writing.

                                                                               4
<PAGE>

10. SIGNATURES/DATE All guarantors who sign are jointly and severally liable for
all obligations under this Guaranty.


This Guaranty is executed as of June 26, 1998.


OYO INSTRUMENTS, INC., GUARANTOR

Dated: June 26, 1998


X /s/ THOMAS T. MCENTIRE
      Thomas T. McEntire, Chief Financial Officer


9777 West Gulf Bank, Suite 10
Houston, Texas  77040

Tax I.D. No.:76-0394284

Address for notices to the Bank:

BANK OF AMERICA TEXAS, N.A.
Houston Commercial Lending, #2552
333 Clay Street, Ste. 3600
Houston, Texas  77002

<PAGE>
BANK OF AMERICA
                                                                   BUSINESS LOAN
                                                             CONTINUING GUARANTY

In this guaranty (the "Guaranty"), "Guarantor", refers to each business
organization or person who signs below. "Bank" refers to Bank of America Texas,
N.A.

1. GUARANTY In consideration of the financial arrangements between Bank and the
Borrowers listed below (each a "Borrower" and collectively, the "Borrowers"),
Guarantor guarantees payment of, and agrees to pay to the order of Bank on
demand, the debts (herein so called) to the Bank of the following Borrower(s):

1.    Oyo Geospace Corporation, Borrower
2.
3.
4.

If two or more Borrowers are named above, the Guarantor guarantees payment of
any Debt they incur together as well as any Debt each one incurs alone. The Debt
includes all loans and advances made by Bank to Borrower and all other
obligations and liabilities of Borrower to Bank, whether now existing or
hereafter incurred or created, whether voluntary or involuntary, whether
individually or with others, whether due or not due, whether absolute or
contingent, whether liquidated or unliquidated or for a determined or
undetermined amount with respect to that certain Business Loan Agreement between
Borrower and Bank dated of even date herewith.

The Debt also includes any and all renewals, extensions, modifications and
increases of each Borrower's obligations to Bank.

Guarantor irrevocably and unconditionally covenants and agrees that it is liable
for the Debt as primary obligor.

Guarantor represents and warrants that it has received or will receive direct or
indirect benefit from the making of this Guaranty and the loans made by Bank to
Borrower, that Guarantor is familiar with the financial condition of Borrower
and the value of any collateral security for the Debt, and that Bank has made no
representations to Guarantor to induce Guarantor to execute this Guaranty.

This Guaranty is continuous. Until revoked, it covers Debts Borrower incurs even
after fully repaying any previous Debts. Each guarantor's obligations remain and
will not be affected in the event of revocation by any other guarantor.

This Guaranty is unconditional. Bank may require Guarantor to pay, and Guarantor
shall not be released or discharged, even if Bank does not:

o     proceed against any borrower, guarantor, or other party;
o     perfect any security interest;
o     proceed against any security; or
o     pursue any other remedy.

Bank may do any of the following without release or discharging Guarantor;

o     release, in full or in part, Borrower, other guarantors, or any other 
      obligors from liability with respect to the Debt;
o     grant any forbearance or compromise to Borrower;
o     release, subordinate its interest in, surrender, or otherwise impair 
      the value of, its interest in any collateral securing the Debt; or
o     fail to exercise diligence, commercial reasonableness, or reasonable care
      in the preservation, enforcement or sale of any collateral securing the
      Debt.

                                                                               1

<PAGE>

Bank may require Guarantor to pay even if a statute of limitations or disability
bars recovery from Borrower, or the Debt is or becomes otherwise unenforceable.

Guarantor waives the benefit of any statute of limitations that would apply to
this Guaranty.

Guarantor hereby waives all notices, including, without limitation, notice of

(a)   acceptance of this Guaranty,
(b)   the extension of credit by Bank to Borrower,
(c)   the occurrence of any breach or default by Borrower in respect of the 
      Debt,
(d)   the sale or foreclosure of any collateral for the Debt, 
(e)   the transfer of the Debt to any third party, 
(f)   intent to accelerate, and 
(g)   acceleration.

Guarantor's obligations are independent of Borrower's obligations, and Bank may
sue Guarantor without suing Borrower.

2. LIMITS OF THE GUARANTY Guarantor shall not be liable for any amount over the
following limit, although Bank may allow the Debt to go above it:

o     the principal amount of $10,000,000.00; plus
o     any interest, fees, and other expenses arising out of, or constituting  
      part of, the Debt.

This Guaranty is in addition to any other guaranty given by Guarantor.

3.    RIGHTS OF THE BANK Bank may from time to time, without notice to or demand
      on Guarantor:

o     change the interest rate on or renew the Debt;
o     accelerate, extend, compromise, or otherwise change the repayment period 
      of the Debt;
o     receive, substitute, or release collateral for the Debt; 
o     sell, otherwise dispose of, or apply collateral in any order; 
o     apply amounts received from anyone other than Guarantor to any 
      unguaranteed part of the Debt;
o     assign or sell the whole or a portion of the Debt and this Guaranty; or
o     foreclose any deed of trust securing the Debt, either by judicial
      foreclosure or power of sale. Even if the foreclosure destroys or lessens
      Guarantor's rights against Borrower, the Guarantor will be liable to Bank 
      for any part of the Debt remaining unpaid after foreclosure.

Bank may, at its option, request periodic financial statements from Guarantor.
Guarantor agrees to supply these statements promptly whenever they are
requested.

Bank may exercise these rights either before or after Guarantor revokes this
Guaranty, and without affecting any obligation under this Guaranty.

Bank may assign this Guaranty, in whole or part, without notice, and Bank and
any assignee or purchaser, or any prospective assignee or purchaser of the Debt,
may exchange financial information about Guarantor with each other in connection
with any assignment or purchase transaction.

If a Borrower is a corporation or partnership, Bank is not required to
investigate the powers of anyone acting on Borrower's behalf.

                                                                               2
<PAGE>

4. PROTECTING THE BANK'S INTEREST Guarantor agrees that any amounts Borrower
owes Guarantor now or in the future are subordinated to Borrower's debt to Bank.
If Bank requires, Guarantor, as a trustee for the Bank, shall collect amounts
Borrower owes Guarantor and pay them to Bank in reduction of the Debt without
affecting or reducing any obligations under this Guaranty.

Guarantor agrees that Guarantor does not have, and hereby waives, any:

o     right of subrogation, reimbursement, indemnification or contribution
      arising from the existence or performance of this Guaranty. This includes
      any such rights arising from contract, statutory law or otherwise, and
      includes any claim of subrogation under the Bankruptcy Code (Title 11 of
      the U.S. Code) or any successor statute;
o     right to enforce a remedy which Bank now has or may later have against
      Borrower;
o     right to participate in security now or later held by Bank; or
o     right to any defense based on a claim that the obligations under this 
      Guaranty are more burdensome or are in excess of Borrower's debt to Bank

Guarantor is solely responsible for obtaining any financial information from
Borrower that guarantor may require. Bank is not required to give Guarantor any
information about Borrower's business operations or financial condition, or any
other notices or demands of any kind, including notices of new debts that may be
incurred by Borrower, notices of default or notice of acceptance of this
Guaranty.

5. SECURITY AND RIGHT OF SETOFF To secure all the Debts covered by this
Guaranty, Guarantor assigns and grants to Bank a security interest in all of
Guarantor's:

o     money;
o     securities;
o     deposit accounts and their proceeds; and
o     any other property maintained in the possession of Bank.

If Borrower defaults, or if any of Guarantor's obligations to Bank are not
fulfilled, Bank may immediately set off any money or proceeds of Guarantor's
deposit accounts, securities, or other property in Bank's possession against the
outstanding Debt.

Bank may also foreclose on any other collateral as provided in the Texas Uniform
Commercial Code and in any security agreements between Bank and Guarantor.

If this Guaranty is secured by real property, Guarantor agrees that any
transfer, assignment, sale or conveyance of such property shall constitute a
default under this Guaranty.

6.    ARBITRATION
(a)   This paragraph concerns the resolution of any controversies or claims
      between Borrower and Bank, including but not limited to those that rise
      from:

      (i)   This Guaranty (including any renewals, extensions or modifications
            of this Guaranty);
      (ii)  Any document, agreement or procedure related to or delivered in
            connection with this Guaranty;
      (iii) Any violation of this Guaranty; or
      (iv)  Any claims for damages resulting from any business conducted between
            Guarantor and Bank, including claims for injury to persons, property
            or business interests (torts).

(b)   At the request of Guarantor or Bank, any such controversies or claims will
      be settled by arbitration in accordance with the United States Arbitration
      Act. THE UNITED STATES ARBITRATION ACT WILL APPLY EVEN THOUGH THIS
      AGREEMENT PROVIDES THAT IT IS GOVERNED BY TEXAS LAW.
(c)   Arbitration proceedings will be administered by the American Arbitration
      Association and will be subject to its commercial rules of arbitration.
(d)   For purposes of the application of the statute of limitation, the filing
      of a lawsuit, and any claim or controversy which may be arbitrated under
      this paragraph is subject to any applicable statute of limitations. The
      arbitrators will have the authority to decide whether any such claim or
      controversy is barred by the statute of limitations and, if so, to dismiss
      the arbitration on that basis.

                                                                               3

<PAGE>

(e)   If there is a dispute as to whether an issue is arbitrable, the
      arbitrators will have the authority to resolve any such dispute.
(f)   The decision that results from an arbitration proceeding may be submitted
      to any authorized court of law to be confirmed and enforced.
(g)   This provision does not limit the right of Guarantor or Bank to:

      (i)   exercise self-help remedies such as setoff;
      (ii)  foreclose against or sell any real or personal property collateral;
      (iii) act in a court of law, before, during or after the arbitration
            proceeding to obtain:

            (A) a provisional or interim remedy; and/or 
            (B) additional or supplementary remedies

(h)   The pursuit of a successful action for provisional, interim, additional or
      supplementary remedies, or the filing of a court action, does not
      constitute a waiver of the right of Guarantor or Bank, including the suing
      party, to submit the controversy or claim to arbitration if the other
      party contests the lawsuit.

7. EXPENSES Guarantor agrees to pay all reasonable attorneys' fees, including
allocated costs of the Bank's in-house counsel, court costs and all other
expenses Bank incurs in enforcing this Guaranty.

8. REVOKING THE GUARANTY Guarantor may revoke this Guaranty as to future
transactions at any time, provided that Guarantor renounces any consideration
given in return for the guaranty of such transactions. Guarantor is obligated on
all credit extended by Bank to Borrower until Bank receives a written notice at
the address shown below revoking this Guaranty.

Any revocation will not affect the Guarantor's obligation for any transactions
that preceded receipt of the written notice, and the Guarantor shall remain
obligated on all debts related to such transactions, even if such debts, before
or after the revocation, have been renewed or modified or any of their terms
shall have been changed in any way.

If this Guaranty is revoked, cancelled or returned, and Bank later must refund
or rescind a payment, or transfer an interest in property back to Borrower, this
Guaranty shall be reinstated as to such payment or interest.

9. ENFORCING THIS GUARANTY THIS GUARANTY IS GOVERNED BY TEXAS LAW, AND BANK MAY
SUE GUARANTOR IN COURTS IN DALLAS COUNTY, TEXAS.

Bank may delay or waive exercising or enforcing any of its rights, including,
without limitation, its rights to setoff and lien, without losing them. Such
rights continue until Bank waives them in writing.

                                                                               4
<PAGE>

10. SIGNATURES/DATE All guarantors who sign are jointly and severally liable for
all obligations under this Guaranty.


This Guaranty is executed as of ____________________, 1998.


OYO GEOSPACE INTERNATIONAL, INC., GUARANTOR

Dated:  ___________________


X________________________________
Thomas T. McEntire, Chief Financial Officer


c/o Abacus Trust & Banking Services, Inc.
Bishops Court Hill
St. Carmichael
Barbados W.I.

Tax I.D. No.: 98-0181902

Address for notices to the Bank:

BANK OF AMERICA TEXAS, N.A.
Houston Commercial Lending, #2552
333 Clay Street, Ste. 3600
Houston, Texas  77002

<PAGE>
BANK OF AMERICA
                                                                   BUSINESS LOAN
                                                             CONTINUING GUARANTY

In this guaranty (the "Guaranty"), "Guarantor", refers to each business
organization or person who signs below. "Bank" refers to Bank of America Texas,
N.A.

1. GUARANTY In consideration of the financial arrangements between Bank and the
Borrowers listed below (each a "Borrower" and collectively, the "Borrowers"),
Guarantor guarantees payment of, and agrees to pay to the order of Bank on
demand, the debts (herein so called) to the Bank of the following Borrower(s):

1.    Oyo Geospace Corporation, Borrower
2.
3.
4.

If two or more Borrowers are named above, the Guarantor guarantees payment of
any Debt they incur together as well as any Debt each one incurs alone. The Debt
includes all loans and advances made by Bank to Borrower and all other
obligations and liabilities of Borrower to Bank, whether now existing or
hereafter incurred or created, whether voluntary or involuntary, whether
individually or with others, whether due or not due, whether absolute or
contingent, whether liquidated or unliquidated or for a determined or
undetermined amount with respect to that certain Business Loan Agreement between
Borrower and Bank dated of even date herewith.

The Debt also includes any and all renewals, extensions, modifications and
increases of each Borrower's obligations to Bank.

Guarantor irrevocably and unconditionally covenants and agrees that it is liable
for the Debt as primary obligor.

Guarantor represents and warrants that it has received or will receive direct or
indirect benefit from the making of this Guaranty and the loans made by Bank to
Borrower, that Guarantor is familiar with the financial condition of Borrower
and the value of any collateral security for the Debt, and that Bank has made no
representations to Guarantor to induce Guarantor to execute this Guaranty.

This Guaranty is continuous. Until revoked, it covers Debts Borrower incurs even
after fully repaying any previous Debts. Each guarantor's obligations remain and
will not be affected in the event of revocation by any other guarantor.

This Guaranty is unconditional. Bank may require Guarantor to pay, and Guarantor
shall not be released or discharged, even if Bank does not:

o     proceed against any borrower, guarantor, or other party;
o     perfect any security interest;
o     proceed against any security; or
o     pursue any other remedy.

Bank may do any of the following without release or discharging Guarantor;

o     release, in full or in part, Borrower, other guarantors, or any other 
      obligors from liability with respect to the Debt;
o     grant any forbearance or compromise to Borrower;
o     release, subordinate its interest in, surrender, or otherwise impair the 
      value of, its interest in any collateral securing the Debt; or
o     fail to exercise diligence, commercial reasonableness, or reasonable care
      in the preservation, enforcement or sale of any collateral securing the
      Debt.

Bank may require Guarantor to pay even if a statute of limitations or disability
bars recovery from Borrower, or the Debt is or becomes otherwise unenforceable.

                                                                               1

<PAGE>

Guarantor waives the benefit of any statute of limitations that would apply to
this Guaranty.

Guarantor hereby waives all notices, including, without limitation, notice of

(a)   acceptance of this Guaranty,
(b)   the extension of credit by Bank to Borrower,
(c)   the occurrence of any breach or default by Borrower in respect of the 
      Debt,
(d)   the sale or foreclosure of any collateral for the Debt, 
(e)   the transfer of the Debt to any third party, 
(f)   intent to accelerate, and 
(g)   acceleration.

Guarantor's obligations are independent of Borrower's obligations, and Bank may
sue Guarantor without suing Borrower.

2. LIMITS OF THE GUARANTY Guarantor shall not be liable for any amount over the
following limit, although Bank may allow the Debt to go above it:

o     the principal amount of $10,000,000.00; plus
o     any interest, fees, and other expenses arising out of, or constituting 
      part of, the Debt.

This Guaranty is in addition to any other guaranty given by Guarantor.

3.    RIGHTS OF THE BANK Bank may from time to time, without notice to or demand
      on Guarantor:

o     change the interest rate on or renew the Debt;
o     accelerate, extend, compromise, or otherwise change the repayment period 
      of the Debt;
o     receive, substitute, or release collateral for the Debt; 
o     sell, otherwise dispose of, or apply collateral in any order; 
o     apply amounts received from anyone other than Guarantor to any 
      unguaranteed part of the Debt;
o     assign or sell the whole or a portion of the Debt and this Guaranty; or
o     foreclose any deed of trust securing the Debt, either by judicial 
      foreclosure or power of sale. Even if the foreclosure destroys or lessens 
      Guarantor's rights against Borrower, the Guarantor will be liable to Bank
      for any part of the Debt remaining unpaid after foreclosure.

Bank may, at its option, request periodic financial statements from Guarantor.
Guarantor agrees to supply these statements promptly whenever they are
requested.

Bank may exercise these rights either before or after Guarantor revokes this
Guaranty, and without affecting any obligation under this Guaranty.

Bank may assign this Guaranty, in whole or part, without notice, and Bank and
any assignee or purchaser, or any prospective assignee or purchaser of the Debt,
may exchange financial information about Guarantor with each other in connection
with any assignment or purchase transaction.

If a Borrower is a corporation or partnership, Bank is not required to
investigate the powers of anyone acting on Borrower's behalf.


4. PROTECTING THE BANK'S INTEREST Guarantor agrees that any amounts Borrower
owes Guarantor now or in the future are subordinated to Borrower's debt to Bank.
If Bank requires, Guarantor, as a trustee for the Bank, shall collect amounts
Borrower owes Guarantor and pay them to Bank in reduction of the Debt without
affecting or reducing any obligations under this Guaranty.

Guarantor agrees that Guarantor does not have, and hereby waives, any:

                                                                               2

<PAGE>

o     right of subrogation, reimbursement, indemnification or contribution
      arising from the existence or performance of this Guaranty. This includes
      any such rights arising from contract, statutory law or otherwise, and
      includes any claim of subrogation under the Bankruptcy Code (Title 11 of
      the U.S. Code) or any successor statute;
o     right to enforce a remedy which Bank now has or may later have against
      Borrower;
o     right to participate in security now or later held by Bank; or
o     right to any defense based on a claim that the obligations under this 
      Guaranty are more burdensome or are in excess of Borrower's debt to Bank

Guarantor is solely responsible for obtaining any financial information from
Borrower that guarantor may require. Bank is not required to give Guarantor any
information about Borrower's business operations or financial condition, or any
other notices or demands of any kind, including notices of new debts that may be
incurred by Borrower, notices of default or notice of acceptance of this
Guaranty.

5. SECURITY AND RIGHT OF SETOFF To secure all the Debts covered by this
Guaranty, Guarantor assigns and grants to Bank a security interest in all of
Guarantor's:

o     money;
o     securities;
o     deposit accounts and their proceeds; and
o     any other property maintained in the possession of Bank.

If Borrower defaults, or if any of Guarantor's obligations to Bank are not
fulfilled, Bank may immediately set off any money or proceeds of Guarantor's
deposit accounts, securities, or other property in Bank's possession against the
outstanding Debt.

Bank may also foreclose on any other collateral as provided in the Texas Uniform
Commercial Code and in any security agreements between Bank and Guarantor.

If this Guaranty is secured by real property, Guarantor agrees that any
transfer, assignment, sale or conveyance of such property shall constitute a
default under this Guaranty.

6.    ARBITRATION
(a)   This paragraph concerns the resolution of any controversies or claims
      between Borrower and Bank, including but not limited to those that rise
      from:

      (i)   This Guaranty (including any renewals, extensions or modifications
            of this Guaranty);
      (ii)  Any document, agreement or procedure related to or delivered in
            connection with this Guaranty;
      (iii) Any violation of this Guaranty; or
      (iv)  Any claims for damages resulting from any business conducted between
            Guarantor and Bank, including claims for injury to persons, property
            or business interests (torts).

(b)   At the request of Guarantor or Bank, any such controversies or claims will
      be settled by arbitration in accordance with the United States Arbitration
      Act. THE UNITED STATES ARBITRATION ACT WILL APPLY EVEN THOUGH THIS
      AGREEMENT PROVIDES THAT IT IS GOVERNED BY TEXAS LAW.
(c)   Arbitration proceedings will be administered by the American Arbitration
      Association and will be subject to its commercial rules of arbitration.
(d)   For purposes of the application of the statute of limitation, the filing
      of a lawsuit, and any claim or controversy which may be arbitrated under
      this paragraph is subject to any applicable statute of limitations. The
      arbitrators will have the authority to decide whether any such claim or
      controversy is barred by the statute of limitations and, if so, to dismiss
      the arbitration on that basis.
(e)   If there is a dispute as to whether an issue is arbitrable, the
      arbitrators will have the authority to resolve any such dispute.
(f)   The decision that results from an arbitration proceeding may be submitted
      to any authorized court of law to be confirmed and enforced.
(g) This provision does not limit the right of Guarantor or Bank to:

                                                                               3

<PAGE>

      (i)   exercise self-help remedies such as setoff;
      (ii) foreclose against or sell any real or personal property collateral;
      (iii) act in a court of law, before, during or after the arbitration
                  proceeding to obtain:

            (A) a provisional or interim remedy; and/or 
            (B) additional or supplementary remedies

(h)   The pursuit of a successful action for provisional, interim, additional or
      supplementary remedies, or the filing of a court action, does not
      constitute a waiver of the right of Guarantor or Bank, including the suing
      party, to submit the controversy or claim to arbitration if the other
      party contests the lawsuit.

7. EXPENSES Guarantor agrees to pay all reasonable attorneys' fees, including
allocated costs of the Bank's in-house counsel, court costs and all other
expenses Bank incurs in enforcing this Guaranty.

8. REVOKING THE GUARANTY Guarantor may revoke this Guaranty as to future
transactions at any time, provided that Guarantor renounces any consideration
given in return for the guaranty of such transactions. Guarantor is obligated on
all credit extended by Bank to Borrower until Bank receives a written notice at
the address shown below revoking this Guaranty.

Any revocation will not affect the Guarantor's obligation for any transactions
that preceded receipt of the written notice, and the Guarantor shall remain
obligated on all debts related to such transactions, even if such debts, before
or after the revocation, have been renewed or modified or any of their terms
shall have been changed in any way.

If this Guaranty is revoked, cancelled or returned, and Bank later must refund
or rescind a payment, or transfer an interest in property back to Borrower, this
Guaranty shall be reinstated as to such payment or interest.

9. ENFORCING THIS GUARANTY THIS GUARANTY IS GOVERNED BY TEXAS LAW, AND BANK MAY
SUE GUARANTOR IN COURTS IN DALLAS COUNTY, TEXAS.

Bank may delay or waive exercising or enforcing any of its rights, including,
without limitation, its rights to setoff and lien, without losing them. Such
rights continue until Bank waives them in writing.

                                                                               4
<PAGE>

10. SIGNATURES/DATE All guarantors who sign are jointly and severally liable for
all obligations under this Guaranty.


This Guaranty is executed as of June 26, 1998.


5404339 AND MORE ROYALTIES COMPANY, GUARANTOR

Dated: June 26, 1998


X /s/ GARY D. OWENS
      Gary D. Owens, President


101 Convention Center Drive, Suite 850
Las Vegas, Nevada  89109

Tax I.D. No.: 88-0384835

Address for notices to the Bank:

BANK OF AMERICA TEXAS, N.A.
Houston Commercial Lending, #2552
333 Clay Street, Ste. 3600
Houston, Texas  77002

<PAGE>
BANK OF AMERICA
                                                                   BUSINESS LOAN
                                                             CONTINUING GUARANTY

In this guaranty (the "Guaranty"), "Guarantor", refers to each business
organization or person who signs below. "Bank" refers to Bank of America Texas,
N.A.

1. GUARANTY In consideration of the financial arrangements between Bank and the
Borrowers listed below (each a "Borrower" and collectively, the "Borrowers"),
Guarantor guarantees payment of, and agrees to pay to the order of Bank on
demand, the debts (herein so called) to the Bank of the following Borrower(s):

1.    Oyo Geospace Corporation, Borrower
2.
3.
4.

If two or more Borrowers are named above, the Guarantor guarantees payment of
any Debt they incur together as well as any Debt each one incurs alone. The Debt
includes all loans and advances made by Bank to Borrower and all other
obligations and liabilities of Borrower to Bank, whether now existing or
hereafter incurred or created, whether voluntary or involuntary, whether
individually or with others, whether due or not due, whether absolute or
contingent, whether liquidated or unliquidated or for a determined or
undetermined amount with respect to that certain Business Loan Agreement between
Borrower and Bank dated of even date herewith.

The Debt also includes any and all renewals, extensions, modifications and
increases of each Borrower's obligations to Bank.

Guarantor irrevocably and unconditionally covenants and agrees that it is liable
for the Debt as primary obligor.

Guarantor represents and warrants that it has received or will receive direct or
indirect benefit from the making of this Guaranty and the loans made by Bank to
Borrower, that Guarantor is familiar with the financial condition of Borrower
and the value of any collateral security for the Debt, and that Bank has made no
representations to Guarantor to induce Guarantor to execute this Guaranty.

This Guaranty is continuous. Until revoked, it covers Debts Borrower incurs even
after fully repaying any previous Debts. Each guarantor's obligations remain and
will not be affected in the event of revocation by any other guarantor.

This Guaranty is unconditional. Bank may require Guarantor to pay, and Guarantor
shall not be released or discharged, even if Bank does not:

o     proceed against any borrower, guarantor, or other party;
o     perfect any security interest;
o     proceed against any security; or
o     pursue any other remedy.

Bank may do any of the following without release or discharging Guarantor;

o     release, in full or in part, Borrower, other guarantors, or any other 
      obligors from liability with respect to the Debt;
o     grant any forbearance or compromise to Borrower;
o     release, subordinate its interest in, surrender, or otherwise impair the 
      value of, its interest in any collateral securing the Debt; or
o     fail to exercise diligence, commercial reasonableness, or reasonable care
      in the preservation, enforcement or sale of any collateral securing the
      Debt.

Bank may require Guarantor to pay even if a statute of limitations or disability
bars recovery from Borrower, or the Debt is or becomes otherwise unenforceable.

                                                                               1

<PAGE>

Guarantor waives the benefit of any statute of limitations that would apply to
this Guaranty.

Guarantor hereby waives all notices, including, without limitation, notice of

(a)   acceptance of this Guaranty,
(b)   the extension of credit by Bank to Borrower,
(c)   the occurrence of any breach or default by Borrower in respect of the 
      Debt,
(d)   the sale or foreclosure of any collateral for the Debt, 
(e)   the transfer of the Debt to any third party, 
(f)   intent to accelerate, and 
(g)   acceleration.

Guarantor's obligations are independent of Borrower's obligations, and Bank may
sue Guarantor without suing Borrower.

2. LIMITS OF THE GUARANTY Guarantor shall not be liable for any amount over the
following limit, although Bank may allow the Debt to go above it:

o     the principal amount of $10,000,000.00; plus
o     any interest, fees, and other expenses arising out of, or constituting  
      part of, the Debt.

This Guaranty is in addition to any other guaranty given by Guarantor.

3.    RIGHTS OF THE BANK Bank may from time to time, without notice to or demand
      on Guarantor:

o     change the interest rate on or renew the Debt;
o     accelerate, extend, compromise, or otherwise change the repayment period 
      of the Debt;
o     receive, substitute, or release collateral for the Debt; 
o     sell, otherwise dispose of, or apply collateral in any order; 
o     apply amounts received from anyone other than Guarantor to any 
      unguaranteed part of the Debt;
o     assign or sell the whole or a portion of the Debt and this Guaranty; or
o     foreclose any deed of trust securing the Debt, either by judicial  
      foreclosure or power of sale. Even if the foreclosure destroys or lessens 
      Guarantor's rights against Borrower, the Guarantor will be liable to Bank 
      for any part of the Debt remaining unpaid after foreclosure.

Bank may, at its option, request periodic financial statements from Guarantor.
Guarantor agrees to supply these statements promptly whenever they are
requested.

Bank may exercise these rights either before or after Guarantor revokes this
Guaranty, and without affecting any obligation under this Guaranty.

Bank may assign this Guaranty, in whole or part, without notice, and Bank and
any assignee or purchaser, or any prospective assignee or purchaser of the Debt,
may exchange financial information about Guarantor with each other in connection
with any assignment or purchase transaction.

If a Borrower is a corporation or partnership, Bank is not required to
investigate the powers of anyone acting on Borrower's behalf.


4. PROTECTING THE BANK'S INTEREST Guarantor agrees that any amounts Borrower
owes Guarantor now or in the future are subordinated to Borrower's debt to Bank.
If Bank requires, Guarantor, as a trustee for the Bank, shall collect amounts
Borrower owes Guarantor and pay them to Bank in reduction of the Debt without
affecting or reducing any obligations under this Guaranty.

Guarantor agrees that Guarantor does not have, and hereby waives, any:

                                                                               2

<PAGE>

o     right of subrogation, reimbursement, indemnification or contribution
      arising from the existence or performance of this Guaranty. This includes
      any such rights arising from contract, statutory law or otherwise, and
      includes any claim of subrogation under the Bankruptcy Code (Title 11 of
      the U.S. Code) or any successor statute;
o     right to enforce a remedy which Bank now has or may later have against
      Borrower;
o     right to participate in security now or later held by Bank; or
o     right to any defense based on a claim that the obligations under this 
      Guaranty are more burdensome or are in excess of Borrower's debt to Bank

Guarantor is solely responsible for obtaining any financial information from
Borrower that guarantor may require. Bank is not required to give Guarantor any
information about Borrower's business operations or financial condition, or any
other notices or demands of any kind, including notices of new debts that may be
incurred by Borrower, notices of default or notice of acceptance of this
Guaranty.

5. SECURITY AND RIGHT OF SETOFF To secure all the Debts covered by this
Guaranty, Guarantor assigns and grants to Bank a security interest in all of
Guarantor's:

o     money;
o     securities;
o     deposit accounts and their proceeds; and
o     any other property maintained in the possession of Bank.

If Borrower defaults, or if any of Guarantor's obligations to Bank are not
fulfilled, Bank may immediately set off any money or proceeds of Guarantor's
deposit accounts, securities, or other property in Bank's possession against the
outstanding Debt.

Bank may also foreclose on any other collateral as provided in the Texas Uniform
Commercial Code and in any security agreements between Bank and Guarantor.

If this Guaranty is secured by real property, Guarantor agrees that any
transfer, assignment, sale or conveyance of such property shall constitute a
default under this Guaranty.

6.    ARBITRATION
(a)   This paragraph concerns the resolution of any controversies or claims
      between Borrower and Bank, including but not limited to those that rise
      from:

      (i)   This Guaranty (including any renewals, extensions or modifications
            of this Guaranty);
      (ii)  Any document, agreement or procedure related to or delivered in
            connection with this Guaranty;
      (iii) Any violation of this Guaranty; or
      (iv)  Any claims for damages resulting from any business conducted between
            Guarantor and Bank, including claims for injury to persons, property
            or business interests (torts).

(b)   At the request of Guarantor or Bank, any such controversies or claims will
      be settled by arbitration in accordance with the United States Arbitration
      Act. THE UNITED STATES ARBITRATION ACT WILL APPLY EVEN THOUGH THIS
      AGREEMENT PROVIDES THAT IT IS GOVERNED BY TEXAS LAW.
(c)   Arbitration proceedings will be administered by the American Arbitration
      Association and will be subject to its commercial rules of arbitration.
(d)   For purposes of the application of the statute of limitation, the filing
      of a lawsuit, and any claim or controversy which may be arbitrated under
      this paragraph is subject to any applicable statute of limitations. The
      arbitrators will have the authority to decide whether any such claim or
      controversy is barred by the statute of limitations and, if so, to dismiss
      the arbitration on that basis.
(e)   If there is a dispute as to whether an issue is arbitrable, the
      arbitrators will have the authority to resolve any such dispute.
(f)   The decision that results from an arbitration proceeding may be submitted
      to any authorized court of law to be confirmed and enforced.
(g)   This provision does not limit the right of Guarantor or Bank to:

                                                                               3

<PAGE>

      (i)   exercise self-help remedies such as setoff;
      (ii)  foreclose against or sell any real or personal property collateral;
      (iii) act in a court of law, before, during or after the arbitration
            proceeding to obtain:

            (A) a provisional or interim remedy; and/or 
            (B) additional or supplementary remedies

(h)   The pursuit of a successful action for provisional, interim, additional or
      supplementary remedies, or the filing of a court action, does not
      constitute a waiver of the right of Guarantor or Bank, including the suing
      party, to submit the controversy or claim to arbitration if the other
      party contests the lawsuit.

7. EXPENSES Guarantor agrees to pay all reasonable attorneys' fees, including
allocated costs of the Bank's in-house counsel, court costs and all other
expenses Bank incurs in enforcing this Guaranty.

8. REVOKING THE GUARANTY Guarantor may revoke this Guaranty as to future
transactions at any time, provided that Guarantor renounces any consideration
given in return for the guaranty of such transactions. Guarantor is obligated on
all credit extended by Bank to Borrower until Bank receives a written notice at
the address shown below revoking this Guaranty.

Any revocation will not affect the Guarantor's obligation for any transactions
that preceded receipt of the written notice, and the Guarantor shall remain
obligated on all debts related to such transactions, even if such debts, before
or after the revocation, have been renewed or modified or any of their terms
shall have been changed in any way.

If this Guaranty is revoked, cancelled or returned, and Bank later must refund
or rescind a payment, or transfer an interest in property back to Borrower, this
Guaranty shall be reinstated as to such payment or interest.

9. ENFORCING THIS GUARANTY THIS GUARANTY IS GOVERNED BY TEXAS LAW, AND BANK MAY
SUE GUARANTOR IN COURTS IN DALLAS COUNTY, TEXAS.

Bank may delay or waive exercising or enforcing any of its rights, including,
without limitation, its rights to setoff and lien, without losing them. Such
rights continue until Bank waives them in writing.

                                                                               4
<PAGE>

10. SIGNATURES/DATE All guarantors who sign are jointly and severally liable for
all obligations under this Guaranty.


This Guaranty is executed as of June 26, 1998.


CONCORD TECHNOLOGIES, INC., GUARANTOR

Dated: June 26, 1998


X /s/ THOMAS T. MCENTIRE
      Thomas T. McEntire, Chief Financial Officer


1830 Kersten
Houston, Texas  77043-3118

Tax I.D. No.: 76-0561467


Address for notices to the Bank:

BANK OF AMERICA TEXAS, N.A.
Houston Commercial Lending, #2552
333 Clay Street, Ste. 3600
Houston, Texas  77002

<PAGE>
BANK OF AMERICA
                                                                   BUSINESS LOAN
                                                             CONTINUING GUARANTY

In this guaranty (the "Guaranty"), "Guarantor", refers to each business
organization or person who signs below. "Bank" refers to Bank of America Texas,
N.A.

1. GUARANTY In consideration of the financial arrangements between Bank and the
Borrowers listed below (each a "Borrower" and collectively, the "Borrowers"),
Guarantor guarantees payment of, and agrees to pay to the order of Bank on
demand, the debts (herein so called) to the Bank of the following Borrower(s):

1.    Oyo Geospace Corporation, Borrower
2.
3.
4.

If two or more Borrowers are named above, the Guarantor guarantees payment of
any Debt they incur together as well as any Debt each one incurs alone. The Debt
includes all loans and advances made by Bank to Borrower and all other
obligations and liabilities of Borrower to Bank, whether now existing or
hereafter incurred or created, whether voluntary or involuntary, whether
individually or with others, whether due or not due, whether absolute or
contingent, whether liquidated or unliquidated or for a determined or
undetermined amount with respect to that certain Business Loan Agreement between
Borrower and Bank dated of even date herewith.

The Debt also includes any and all renewals, extensions, modifications and
increases of each Borrower's obligations to Bank.

Guarantor irrevocably and unconditionally covenants and agrees that it is liable
for the Debt as primary obligor.

Guarantor represents and warrants that it has received or will receive direct or
indirect benefit from the making of this Guaranty and the loans made by Bank to
Borrower, that Guarantor is familiar with the financial condition of Borrower
and the value of any collateral security for the Debt, and that Bank has made no
representations to Guarantor to induce Guarantor to execute this Guaranty.

This Guaranty is continuous. Until revoked, it covers Debts Borrower incurs even
after fully repaying any previous Debts. Each guarantor's obligations remain and
will not be affected in the event of revocation by any other guarantor.

This Guaranty is unconditional. Bank may require Guarantor to pay, and Guarantor
shall not be released or discharged, even if Bank does not:

o     proceed against any borrower, guarantor, or other party;
o     perfect any security interest;
o     proceed against any security; or
o     pursue any other remedy.

Bank may do any of the following without release or discharging Guarantor;

o     release, in full or in part, Borrower, other guarantors, or any other 
      obligors from liability with respect to the Debt;
o     grant any forbearance or compromise to Borrower;
o     release, subordinate its interest in, surrender, or otherwise impair the 
      value of, its interest in any collateral securing the Debt; or
o     fail to exercise diligence, commercial reasonableness, or reasonable care
      in the preservation, enforcement or sale of any collateral securing the
      Debt.

Bank may require Guarantor to pay even if a statute of limitations or disability
bars recovery from Borrower, or the Debt is or becomes otherwise unenforceable.

                                                                               1

<PAGE>

Guarantor waives the benefit of any statute of limitations that would apply to
this Guaranty.

Guarantor hereby waives all notices, including, without limitation, notice of

(a)   acceptance of this Guaranty,
(b)   the extension of credit by Bank to Borrower,
(c)   the occurrence of any breach or default by Borrower in respect of the 
      Debt,
(d)   the sale or foreclosure of any collateral for the Debt, 
(e)   the transfer of the Debt to any third party, 
(f)   intent to accelerate, and 
(g)   acceleration.

Guarantor's obligations are independent of Borrower's obligations, and Bank may
sue Guarantor without suing Borrower.

2. LIMITS OF THE GUARANTY Guarantor shall not be liable for any amount over the
following limit, although Bank may allow the Debt to go above it:

o     the principal amount of $10,000,000.00; plus
o     any interest, fees, and other expenses arising out of, or constituting
      part of, the Debt.

This Guaranty is in addition to any other guaranty given by Guarantor.

3.    RIGHTS OF THE BANK Bank may from time to time, without notice to or demand
      on Guarantor:

o     change the interest rate on or renew the Debt;
o     accelerate, extend, compromise, or otherwise change the repayment period 
      of the Debt;
o     receive, substitute, or release collateral for the Debt; 
o     sell, otherwise dispose of, or apply collateral in any order; 
o     apply amounts received from anyone other than Guarantor to any 
      unguaranteed part of the Debt;
o     assign or sell the whole or a portion of the Debt and this Guaranty; or
o     foreclose any deed of trust securing the Debt, either by judicial
      foreclosure or power of sale. Even if the foreclosure destroys or lessens 
      Guarantor's rights against Borrower, the Guarantor will be liable to Bank 
      for any part of the Debt remaining unpaid after foreclosure.

Bank may, at its option, request periodic financial statements from Guarantor.
Guarantor agrees to supply these statements promptly whenever they are
requested.

Bank may exercise these rights either before or after Guarantor revokes this
Guaranty, and without affecting any obligation under this Guaranty.

Bank may assign this Guaranty, in whole or part, without notice, and Bank and
any assignee or purchaser, or any prospective assignee or purchaser of the Debt,
may exchange financial information about Guarantor with each other in connection
with any assignment or purchase transaction.

If a Borrower is a corporation or partnership, Bank is not required to
investigate the powers of anyone acting on Borrower's behalf.

                                                                               2
<PAGE>

4. PROTECTING THE BANK'S INTEREST Guarantor agrees that any amounts Borrower
owes Guarantor now or in the future are subordinated to Borrower's debt to Bank.
If Bank requires, Guarantor, as a trustee for the Bank, shall collect amounts
Borrower owes Guarantor and pay them to Bank in reduction of the Debt without
affecting or reducing any obligations under this Guaranty.

Guarantor agrees that Guarantor does not have, and hereby waives, any:

o     right of subrogation, reimbursement, indemnification or contribution
      arising from the existence or performance of this Guaranty. This includes
      any such rights arising from contract, statutory law or otherwise, and
      includes any claim of subrogation under the Bankruptcy Code (Title 11 of
      the U.S. Code) or any successor statute;
o     right to enforce a remedy which Bank now has or may later have against
      Borrower;
o     right to participate in security now or later held by Bank; or
o     right to any defense based on a claim that the obligations under this 
      Guaranty are more burdensome or are in excess of Borrower's debt to Bank

Guarantor is solely responsible for obtaining any financial information from
Borrower that guarantor may require. Bank is not required to give Guarantor any
information about Borrower's business operations or financial condition, or any
other notices or demands of any kind, including notices of new debts that may be
incurred by Borrower, notices of default or notice of acceptance of this
Guaranty.

5. SECURITY AND RIGHT OF SETOFF To secure all the Debts covered by this
Guaranty, Guarantor assigns and grants to Bank a security interest in all of
Guarantor's:

o     money;
o     securities;
o     deposit accounts and their proceeds; and
o     any other property maintained in the possession of Bank.

If Borrower defaults, or if any of Guarantor's obligations to Bank are not
fulfilled, Bank may immediately set off any money or proceeds of Guarantor's
deposit accounts, securities, or other property in Bank's possession against the
outstanding Debt.

Bank may also foreclose on any other collateral as provided in the Texas Uniform
Commercial Code and in any security agreements between Bank and Guarantor.

If this Guaranty is secured by real property, Guarantor agrees that any
transfer, assignment, sale or conveyance of such property shall constitute a
default under this Guaranty.

6.    ARBITRATION
(a)   This paragraph concerns the resolution of any controversies or claims
      between Borrower and Bank, including but not limited to those that rise
      from:

      (i)   This Guaranty (including any renewals, extensions or modifications
            of this Guaranty);
      (ii)  Any document, agreement or procedure related to or delivered in
            connection with this Guaranty;
      (iii) Any violation of this Guaranty; or
      (iv)  Any claims for damages resulting from any business conducted between
            Guarantor and Bank, including claims for injury to persons, property
            or business interests (torts).

(b)   At the request of Guarantor or Bank, any such controversies or claims will
      be settled by arbitration in accordance with the United States Arbitration
      Act. THE UNITED STATES ARBITRATION ACT WILL APPLY EVEN THOUGH THIS
      AGREEMENT PROVIDES THAT IT IS GOVERNED BY TEXAS LAW.
(c)   Arbitration proceedings will be administered by the American Arbitration
      Association and will be subject to its commercial rules of arbitration.
(d)   For purposes of the application of the statute of limitation, the filing
      of a lawsuit, and any claim or controversy which may be arbitrated under
      this paragraph is subject to any applicable statute of limitations. The
      arbitrators will have the authority to decide whether any such claim or
      controversy is barred by the statute of limitations and, if so, to dismiss
      the arbitration on that basis.

                                                                               3

<PAGE>

(e)   If there is a dispute as to whether an issue is arbitrable, the
      arbitrators will have the authority to resolve any such dispute.
(f)   The decision that results from an arbitration proceeding may be submitted
      to any authorized court of law to be confirmed and enforced.
(g) This provision does not limit the right of Guarantor or Bank to:

      (i)   exercise self-help remedies such as setoff;
      (ii) foreclose against or sell any real or personal property collateral;
      (iii) act in a court of law, before, during or after the arbitration
                  proceeding to obtain:

            (A) a provisional or interim remedy; and/or 
            (B) additional or supplementary remedies

(h)   The pursuit of a successful action for provisional, interim, additional or
      supplementary remedies, or the filing of a court action, does not
      constitute a waiver of the right of Guarantor or Bank, including the suing
      party, to submit the controversy or claim to arbitration if the other
      party contests the lawsuit.

7. EXPENSES Guarantor agrees to pay all reasonable attorneys' fees, including
allocated costs of the Bank's in-house counsel, court costs and all other
expenses Bank incurs in enforcing this Guaranty.

8. REVOKING THE GUARANTY Guarantor may revoke this Guaranty as to future
transactions at any time, provided that Guarantor renounces any consideration
given in return for the guaranty of such transactions. Guarantor is obligated on
all credit extended by Bank to Borrower until Bank receives a written notice at
the address shown below revoking this Guaranty.

Any revocation will not affect the Guarantor's obligation for any transactions
that preceded receipt of the written notice, and the Guarantor shall remain
obligated on all debts related to such transactions, even if such debts, before
or after the revocation, have been renewed or modified or any of their terms
shall have been changed in any way.

If this Guaranty is revoked, cancelled or returned, and Bank later must refund
or rescind a payment, or transfer an interest in property back to Borrower, this
Guaranty shall be reinstated as to such payment or interest.

9. ENFORCING THIS GUARANTY THIS GUARANTY IS GOVERNED BY TEXAS LAW, AND BANK MAY
SUE GUARANTOR IN COURTS IN DALLAS COUNTY, TEXAS.

Bank may delay or waive exercising or enforcing any of its rights, including,
without limitation, its rights to setoff and lien, without losing them. Such
rights continue until Bank waives them in writing.

                                                                               4
<PAGE>

10. SIGNATURES/DATE All guarantors who sign are jointly and severally liable for
all obligations under this Guaranty.


This Guaranty is executed as of June 26, 1998.


HOUSTON GEOPHYSICAL PRODUCTS, INC., GUARANTOR

Dated: June 26, 1998


X /s/ THOMAS T. MCENTIRE
      Thomas T. McEntire, Chief Financial Officer


507 Allen Genoa Road
Houston, Texas  77017

Tax I.D. No.: 74-2138710

Address for notices to the Bank:

BANK OF AMERICA TEXAS, N.A.
Houston Commercial Lending, #2552
333 Clay Street, Ste. 3600
Houston, Texas  77002

<PAGE>
BANK OF AMERICA

                                                                   BUSINESS LOAN
                                                             CONTINUING GUARANTY

In this guaranty (the "Guaranty"), "Guarantor", refers to each business
organization or person who signs below. "Bank" refers to Bank of America Texas,
N.A.

1. GUARANTY In consideration of the financial arrangements between Bank and the
Borrowers listed below (each a "Borrower" and collectively, the "Borrowers"),
Guarantor guarantees payment of, and agrees to pay to the order of Bank on
demand, the debts (herein so called) to the Bank of the following Borrower(s):

1.    Oyo Geospace Corporation, Borrower
2.
3.
4.

If two or more Borrowers are named above, the Guarantor guarantees payment of
any Debt they incur together as well as any Debt each one incurs alone. The Debt
includes all loans and advances made by Bank to Borrower and all other
obligations and liabilities of Borrower to Bank, whether now existing or
hereafter incurred or created, whether voluntary or involuntary, whether
individually or with others, whether due or not due, whether absolute or
contingent, whether liquidated or unliquidated or for a determined or
undetermined amount with respect to that certain Business Loan Agreement between
Borrower and Bank dated of even date herewith.

The Debt also includes any and all renewals, extensions, modifications and
increases of each Borrower's obligations to Bank.

Guarantor irrevocably and unconditionally covenants and agrees that it is liable
for the Debt as primary obligor.

Guarantor represents and warrants that it has received or will receive direct or
indirect benefit from the making of this Guaranty and the loans made by Bank to
Borrower, that Guarantor is familiar with the financial condition of Borrower
and the value of any collateral security for the Debt, and that Bank has made no
representations to Guarantor to induce Guarantor to execute this Guaranty.

This Guaranty is continuous. Until revoked, it covers Debts Borrower incurs even
after fully repaying any previous Debts. Each guarantor's obligations remain and
will not be affected in the event of revocation by any other guarantor.

This Guaranty is unconditional. Bank may require Guarantor to pay, and Guarantor
shall not be released or discharged, even if Bank does not:

o     proceed against any borrower, guarantor, or other party;
o     perfect any security interest;
o     proceed against any security; or
o     pursue any other remedy.

Bank may do any of the following without release or discharging Guarantor;

o     release, in full or in part, Borrower, other guarantors, or any other 
      obligors from liability with respect to the Debt;
o     grant any forbearance or compromise to Borrower;
o     release,  subordinate its interest in, surrender, or otherwise impair the 
      value of, its interest in any collateral securing the Debt; or
o     fail to exercise diligence, commercial reasonableness, or reasonable care
      in the preservation, enforcement or sale of any collateral securing the
      Debt.
                                                                               1

<PAGE>

Bank may require Guarantor to pay even if a statute of limitations or disability
bars recovery from Borrower, or the Debt is or becomes otherwise unenforceable.

Guarantor waives the benefit of any statute of limitations that would apply to
this Guaranty.

Guarantor hereby waives all notices, including, without limitation, notice of

(a)   acceptance of this Guaranty,
(b)   the extension of credit by Bank to Borrower,
(c)   the occurrence of any breach or default by Borrower in respect of the 
      Debt,
(d)   the sale or foreclosure of any collateral for the Debt, 
(e)   the transfer of the Debt to any third party, 
(f)   intent to accelerate, and 
(g)   acceleration.

Guarantor's obligations are independent of Borrower's obligations, and Bank may
sue Guarantor without suing Borrower.

2. LIMITS OF THE GUARANTY Guarantor shall not be liable for any amount over the
following limit, although Bank may allow the Debt to go above it:

o     the principal amount of $10,000,000.00; plus
o     any interest, fees, and other expenses arising out of, or constituting  
      part of, the Debt.

This Guaranty is in addition to any other guaranty given by Guarantor.

3.    RIGHTS OF THE BANK Bank may from time to time, without notice to or demand
      on Guarantor:

o     change the interest rate on or renew the Debt;
o     accelerate, extend, compromise, or otherwise change the repayment period 
      of the Debt;
o     receive, substitute, or release collateral for the Debt; 
o     sell, otherwise dispose of, or apply collateral in any order; 
o     apply amounts received from anyone other than Guarantor to any 
      unguaranteed part of the Debt;
o     assign or sell the whole or a portion of the Debt and this Guaranty; or
o     foreclose any deed of trust securing the Debt, either by judicial 
      foreclosure or power of sale. Even if the foreclosure destroys or lessens 
      Guarantor's rights against Borrower, the Guarantor will be liable to Bank 
      for any part of the Debt remaining unpaid after foreclosure.

Bank may, at its option, request periodic financial statements from Guarantor.
Guarantor agrees to supply these statements promptly whenever they are
requested.

Bank may exercise these rights either before or after Guarantor revokes this
Guaranty, and without affecting any obligation under this Guaranty.

Bank may assign this Guaranty, in whole or part, without notice, and Bank and
any assignee or purchaser, or any prospective assignee or purchaser of the Debt,
may exchange financial information about Guarantor with each other in connection
with any assignment or purchase transaction.

If a Borrower is a corporation or partnership, Bank is not required to
investigate the powers of anyone acting on Borrower's behalf.

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4. PROTECTING THE BANK'S INTEREST Guarantor agrees that any amounts Borrower
owes Guarantor now or in the future are subordinated to Borrower's debt to Bank.
If Bank requires, Guarantor, as a trustee for the Bank, shall collect amounts
Borrower owes Guarantor and pay them to Bank in reduction of the Debt without
affecting or reducing any obligations under this Guaranty.

Guarantor agrees that Guarantor does not have, and hereby waives, any:

o     right of subrogation, reimbursement, indemnification or contribution
      arising from the existence or performance of this Guaranty. This includes
      any such rights arising from contract, statutory law or otherwise, and
      includes any claim of subrogation under the Bankruptcy Code (Title 11 of
      the U.S. Code) or any successor statute;
o     right to enforce a remedy which Bank now has or may later have against
      Borrower;
o     right to participate in security now or later held by Bank; or
o     right to any defense based on a claim that the obligations under this 
      Guaranty are more burdensome or are in excess of Borrower's debt to Bank

Guarantor is solely responsible for obtaining any financial information from
Borrower that guarantor may require. Bank is not required to give Guarantor any
information about Borrower's business operations or financial condition, or any
other notices or demands of any kind, including notices of new debts that may be
incurred by Borrower, notices of default or notice of acceptance of this
Guaranty.

5. SECURITY AND RIGHT OF SETOFF To secure all the Debts covered by this
Guaranty, Guarantor assigns and grants to Bank a security interest in all of
Guarantor's:

o     money;
o     securities;
o     deposit accounts and their proceeds; and
o     any other property maintained in the possession of Bank.

If Borrower defaults, or if any of Guarantor's obligations to Bank are not
fulfilled, Bank may immediately set off any money or proceeds of Guarantor's
deposit accounts, securities, or other property in Bank's possession against the
outstanding Debt.

Bank may also foreclose on any other collateral as provided in the Texas Uniform
Commercial Code and in any security agreements between Bank and Guarantor.

If this Guaranty is secured by real property, Guarantor agrees that any
transfer, assignment, sale or conveyance of such property shall constitute a
default under this Guaranty.

6.    ARBITRATION
(a)   This paragraph concerns the resolution of any controversies or claims
      between Borrower and Bank, including but not limited to those that rise
      from:

      (i)   This Guaranty (including any renewals, extensions or modifications
            of this Guaranty);
      (ii)  Any document, agreement or procedure related to or delivered in
            connection with this Guaranty;
      (iii) Any violation of this Guaranty; or
      (iv)  Any claims for damages resulting from any business conducted between
            Guarantor and Bank, including claims for injury to persons, property
            or business interests (torts).

(b)   At the request of Guarantor or Bank, any such controversies or claims will
      be settled by arbitration in accordance with the United States Arbitration
      Act. THE UNITED STATES ARBITRATION ACT WILL APPLY EVEN THOUGH THIS
      AGREEMENT PROVIDES THAT IT IS GOVERNED BY TEXAS LAW.
(c)   Arbitration proceedings will be administered by the American Arbitration
      Association and will be subject to its commercial rules of arbitration.
(d)   For purposes of the application of the statute of limitation, the filing
      of a lawsuit, and any claim or controversy which may be arbitrated under
      this paragraph is subject to any applicable statute of limitations. The
      arbitrators will have the authority to decide whether any such claim or
      controversy is barred by the statute of limitations and, if so, to dismiss
      the arbitration on that basis.

                                                                               3

<PAGE>

(e)   If there is a dispute as to whether an issue is arbitrable, the
      arbitrators will have the authority to resolve any such dispute.
(f)   The decision that results from an arbitration proceeding may be submitted
      to any authorized court of law to be confirmed and enforced.
(g) This provision does not limit the right of Guarantor or Bank to:

      (i)   exercise self-help remedies such as setoff;
      (ii) foreclose against or sell any real or personal property collateral;
      (iii) act in a court of law, before, during or after the arbitration
                  proceeding to obtain:

            (A) a provisional or interim remedy; and/or 
            (B) additional or supplementary remedies

(h)   The pursuit of a successful action for provisional, interim, additional or
      supplementary remedies, or the filing of a court action, does not
      constitute a waiver of the right of Guarantor or Bank, including the suing
      party, to submit the controversy or claim to arbitration if the other
      party contests the lawsuit.

7. EXPENSES Guarantor agrees to pay all reasonable attorneys' fees, including
allocated costs of the Bank's in-house counsel, court costs and all other
expenses Bank incurs in enforcing this Guaranty.

8. REVOKING THE GUARANTY Guarantor may revoke this Guaranty as to future
transactions at any time, provided that Guarantor renounces any consideration
given in return for the guaranty of such transactions. Guarantor is obligated on
all credit extended by Bank to Borrower until Bank receives a written notice at
the address shown below revoking this Guaranty.

Any revocation will not affect the Guarantor's obligation for any transactions
that preceded receipt of the written notice, and the Guarantor shall remain
obligated on all debts related to such transactions, even if such debts, before
or after the revocation, have been renewed or modified or any of their terms
shall have been changed in any way.

If this Guaranty is revoked, cancelled or returned, and Bank later must refund
or rescind a payment, or transfer an interest in property back to Borrower, this
Guaranty shall be reinstated as to such payment or interest.

9. ENFORCING THIS GUARANTY THIS GUARANTY IS GOVERNED BY TEXAS LAW, AND BANK MAY
SUE GUARANTOR IN COURTS IN DALLAS COUNTY, TEXAS.

Bank may delay or waive exercising or enforcing any of its rights, including,
without limitation, its rights to setoff and lien, without losing them. Such
rights continue until Bank waives them in writing.

                                                                               4
<PAGE>

10. SIGNATURES/DATE All guarantors who sign are jointly and severally liable for
all obligations under this Guaranty.


This Guaranty is executed as of ____________________, 1998.


OYO INSTRUMENTS UK, LTD., GUARANTOR

Dated:  ___________________


X________________________________
Roger Caldwell, Managing Director and Secretary

F3 Bramingham Business Park
Enterprise Way, Luton
Bedshire LU3 4BU
England

Tax I.D. No.:not applicable for UK entity


Address for notices to the Bank:

BANK OF AMERICA TEXAS, N.A.
Houston Commercial Lending, #2552
333 Clay Street, Ste. 3600
Houston, Texas  77002