<PAGE>   1
 
================================================================================
 
                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                             ---------------------
                                      1996
 
                                  FORM 10-K/A
   
                                AMENDMENT NO. 1
    
                             ---------------------
(MARK ONE)
 
      [X]     ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
                        SECURITIES EXCHANGE ACT OF 1934
 
                  FOR THE FISCAL YEAR ENDED DECEMBER 31, 1996
 
                                       OR
 
      [ ]   TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
               SECURITIES EXCHANGE ACT OF 1934 [NO FEE REQUIRED]
 
           FOR THE TRANSITION PERIOD FROM             TO
 
                         COMMISSION FILE NUMBER 1-13108
 
                             VASTAR RESOURCES, INC.
             (Exact name of registrant as specified in its charter)
                             ---------------------
 
<TABLE>
<S>                                                 <C>
                     DELAWARE                                           95-4446177
   (State or other jurisdiction of incorporation           (I.R.S. Employer Identification No.)
                 or organization)
 
               15375 MEMORIAL DRIVE
                  HOUSTON, TEXAS                                           77079
     (Address of principal executive offices)                           (Zip Code)
</TABLE>
 
                                 (281) 584-6000
              (Registrant's telephone number, including area code)
                             ---------------------
          Securities registered pursuant to Section 12(b) of the Act:
 
<TABLE>
<CAPTION>
                TITLE OF EACH CLASS                      NAME OF EACH EXCHANGE ON WHICH REGISTERED
                -------------------                      -----------------------------------------
<S>                                                 <C>
      Common Stock, Par Value $.01 Per Share                      New York Stock Exchange
</TABLE>
 
       Securities registered pursuant to Section 12 (g) of the Act: NONE
 
     INDICATE BY CHECK MARK WHETHER THE REGISTRANT (1) HAS FILED ALL REPORTS
REQUIRED TO BE FILED BY SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF
1934 DURING THE PRECEDING 12 MONTHS (OR FOR SUCH SHORTER PERIOD THAT THE
REGISTRANT WAS REQUIRED TO FILE SUCH REPORTS) AND (2) HAS BEEN SUBJECT TO SUCH
FILING REQUIREMENTS FOR THE PAST 90 DAYS.  YES  X   NO ____
 
     INDICATE BY CHECK MARK IF DISCLOSURE OF DELINQUENT FILERS PURSUANT TO ITEM
405 OF REGULATION S-K IS NOT CONTAINED HEREIN, AND WILL NOT BE CONTAINED, TO THE
BEST OF REGISTRANT'S KNOWLEDGE, IN DEFINITIVE PROXY OR INFORMATION STATEMENTS
INCORPORATED BY REFERENCE IN PART III OF THIS FORM 10-K OR ANY AMENDMENT TO THIS
FORM 10-K. ____
 
     The aggregate market value of the Registrant's voting stock held by
non-affiliates on March 3, 1997, based on the closing price on the New York
Stock Exchange composite tape on that date of $29, was $500,555,950.
 
     As of March 3, 1997, there were 97,260,551 shares of Common Stock
outstanding.
 
                      DOCUMENTS INCORPORATED BY REFERENCE
 
     Portions of the Registrant's definitive proxy statement for the 1997 Annual
Meeting of Stockholders to be held on May 21, 1997, which will be filed with the
Securities and Exchange Commission within 120 days after December 31, 1996, are
incorporated by reference into Part III.
================================================================================
<PAGE>   2

   
This Amendment No. 1 on Form 10-K/A (this "Amendment") amends Part IV of the
Annual Report on Form 10-K of Vastar Resources, Inc. (the "Company") for the
fiscal year ended December 31, 1996 (the "Form 10-K"), to correct certain
inadvertent typographical errors and omissions contained therein and to revise
the Company's Financial Data Schedule (Exhibit 27) to correct an inadvertent
error relating to the "Common" and "Other-SE" tags. In accordance with Rule
12b-15 promulgated under the Securities Exchange Act of 1934, as amended, this
Amendment sets forth the complete text to Part IV of the Form 10-K and 
Exhibit 27, as amended.
    



<PAGE>   3
 
                                    PART IV
 
ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K.
 
     (a) The following documents are filed as part of this report:
 
<TABLE>
<S>                      <C>
1 and 2                  -- Financial Statements and Financial Statement Schedules:
                            These documents are listed in the Index to Consolidated
                            Financial Statements in Item 8 hereof.
</TABLE>
 
3. Exhibits:
 
   
<TABLE>
<S>                      <C>
         3.1             -- Second Restated Certificate of Incorporation of Vastar
                            Resources, Inc. ("Vastar") filed with the State of
                            Delaware on May 17, 1996 (filed with the Securities and
                            Exchange Commission (the "Commission") on August 7, 1996
                            as Exhibit 3 to Vastar's report on Form 10-Q for the
                            quarterly period ended June 30, 1996 (Commission File No.
                            1-13108) and incorporated herein by reference)
         3.2             -- By-Laws of Vastar (filed with the Commission as Exhibit
                            3.2 to Vastar's report on Form 10-K for the year ended
                            December 31, 1994 (Commission File No. 1-13108) and
                            incorporated herein by reference)
         4.1             -- Form of certificate evidencing Common Stock (filed with
                            the Commission on June 23, 1994 as Exhibit 4 to Amendment
                            No. 4 to Vastar's Registration Statement on Form S-1
                            (Registration No. 33-74536) (Commission File No. 1-13108)
                            and incorporated herein by reference)
         4.2(a)          -- Indenture dated as of January 1, 1995 between Vastar and
                            NationsBank of Texas, N.A. (filed with the Commission as
                            Exhibit 4.2 to Vastar's report on Form 10-K for the year
                            ended December 31, 1994 (Commission File No. 1-13108) and
                            incorporated herein by reference)
         4.2(b)          -- Supplemental Indenture, dated May 18, 1995, by and among
                            Vastar, NationsBank of Texas, N.A., Harris Trust and
                            Savings Bank and Bank of Montreal Trust Company,
                            effective May 25, 1995 (filed with the Commission on 
                            June 9, 1995 as Exhibit 4 to Vastar's Current Report 
                            on Form 8-K dated May 5, 1995 (Commission File No. 
                            1-13108) and incorporated herein by reference)
        10.1(a)          -- Amendment No. 1 to Credit Agreement, dated as of March
                            29, 1996, among Vastar, the Banks Parties thereto, the
                            Co-Agents listed therein and Morgan Guaranty Trust
                            Company of New York, as Agent (filed with the Commission
                            on May 2, 1996 as Exhibit 10 to Vastar's Quarterly Report
                            on Form 10-Q for the quarterly period ended March 31,
                            1996 (Commission File No. 1-13108) and incorporated
                            herein by reference)
        10.1(b)          -- $800,000,000 Credit Agreement, dated as of May 5, 1995,
                            among Vastar, the Banks Parties thereto, the Co-Agents
                            listed therein and Morgan Guaranty Trust Company of New
                            York, as Agent (filed with the Commission on June 9, 1995
                            as Exhibit 10.3 to Vastar's Current Report on Form 8-K
                            dated May 5, 1995 (Commission File No. 1-13108) and
                            incorporated herein by reference)
        10.2             -- General Conveyance and Assumption Agreement, dated
                            October 8, 1993, modified as of December 13, 1993 and
                            December 22, 1993, between Vastar and Atlantic Richfield
                            Company ("ARCO") (filed with the Commission on January
                            28, 1994 as Exhibit 10.2 to Vastar's Registration
                            Statement on Form S-1 (Registration No. 33-74536)
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)
</TABLE>
    
                                      50
<PAGE>   4
   
<TABLE>
<S>                      <C>
        10.3             -- Cross-Indemnification Agreement, dated as of October 1,
                            1993, between Vastar and ARCO (filed with the Commission
                            on January 28, 1994 as Exhibit 10.3 to Vastar's
                            Registration Statement on Form S-1 (Registration No.
                            33-74536) (Commission File No. 1-13108) and incorporated
                            herein by reference)
        10.4(a)          -- Tax Sharing Agreement, dated as of October 1, 1993,
                            between Vastar and ARCO (filed with the Commission on
                            January 28, 1994 as Exhibit 10.4 to Vastar's Registration
                            Statement on Form S-1 (Registration No. 33-74536)
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)
        10.4(b)          -- First Amendment to Tax Sharing Agreement, dated as of
                            June 1, 1995, between Vastar, F&H Pipeline Company, Grant
                            Gathering Company, Wilburton Hub, Inc., Vastar Gas
                            Marketing, Inc. and ARCO (filed with the Commission as
                            Exhibit 10 to Vastar's report on Form 10-Q for the
                            quarterly period ended June 30, 1995 (Commission File 
                            No. 1-13108) and incorporated herein by reference)
        10.5             -- Corporate Services Agreement, dated as of February 22,
                            1994, between Vastar and ARCO (filed with the Commission
                            on March 23, 1994 as Exhibit 10.5 to Amendment No. 1 to
                            Vastar's Registration Statement on Form S-1 (Registration
                            No. 33-74536) (Commission File No. 1-13108) and
                            incorporated herein by reference)
        10.6             -- ARCO Exploration and Production Technology Technical
                            Services Agreement, dated as of October 1, 1993, between
                            Vastar and ARCO (filed with the Commission on January 28,
                            1994 as Exhibit 10.7 to Vastar's Registration Statement
                            on Form S-1 (Registration No. 33-74536) (Commission File
                            No. 1-13108) and incorporated herein by reference)
        10.7             -- Insurance Services Agreement, dated as of March 24, 1994,
                            between Vastar and ARCO (filed with the Commission on May
                            26, 1994 as Exhibit 10.8 to Amendment No. 2 to Vastar's
                            Registration Statement on Form S-1 (Registration No.
                            33-74536) (Commission File No. 1-13108) and incorporated
                            herein by reference)
        10.8             -- Agreement for the Purchase and Sale of Natural Gas
                            Liquids, dated December 21, 1993, between Vastar and ARCO
                            (filed with the Commission on January 28, 1994 as Exhibit
                            10.9 to Vastar's Registration Statement on Form S-1
                            (Registration No. 33-74536) (Commission File No. 1-13108)
                            and incorporated herein by reference)
        10.9             -- Technology Assignment Agreement, dated as of October 1,
                            1993, between Vastar and ARCO (filed with the Commission
                            on January 28, 1994 as Exhibit 10.11 to Vastar's
                            Registration Statement on Form S-1 (Registration No.
                            33-74536) (Commission File No. 1-13108) and incorporated
                            herein by reference)
        10.10            -- Technology Undivided Interest Assignment Agreement, dated
                            as of October 1, 1993, between Vastar and ARCO (filed
                            with the Commission on January 28, 1994 as Exhibit 10.12
                            to Vastar's Registration Statement on Form S-1
                            (Registration No. 33-74536) (Commission File No. 1-13108)
                            and incorporated herein by reference)
        10.11            -- Information Technology License Agreement, dated as of
                            October 1, 1993, between Vastar and ARCO (filed with the
                            Commission on January 28, 1994 as Exhibit 10.13 to
                            Vastar's Registration Statement on Form S-1 (Registration
                            No. 33-74536) (Commission File No. 1-13108) and
                            incorporated herein by reference)
</TABLE>
    

                                      51
<PAGE>   5
   
<TABLE>
<S>                      <C>
        10.12            -- Intellectual Property License Agreement, dated as of
                            October 1, 1993, between Vastar and ARCO (filed with the
                            Commission on January 28, 1994 as Exhibit 10.14 to
                            Vastar's Registration Statement on Form S-1 (Registration
                            No. 33-74536) (Commission File No. 1-13108) and
                            incorporated herein by reference)
        10.13            -- Third Party Technology Assignment Agreement, dated as of
                            October 1, 1993, between Vastar and ARCO (filed with the
                            Commission on January 28, 1994 as Exhibit 10.15 to
                            Vastar's Registration Statement on Form S-1 (Registration
                            No. 33-74536) (Commission File No. 1-13108) and
                            incorporated herein by reference)
        10.14            -- Share Purchase Option and Business Opportunities
                            Agreement, dated as of May 19, 1994, between Vastar and
                            ARCO (filed with the Commission on June 7, 1994 as
                            Exhibit 10.16 to Amendment No. 3 to Vastar's Registration
                            Statement on Form S-1 (Registration No. 33-74536)
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)
        10.15            -- Form of Company's Indemnity Agreement with officers and
                            directors (filed with the Commission on January 28, 1994
                            as Exhibit 10.17 to Vastar's Registration Statement on
                            Form S-1 (Registration No. 33-74536) (Commission File No.
                            1-13108) and incorporated herein by reference)(2)
        10.16            -- Gas Sales and Purchase Agreement, dated December 15,
                            1993, between Vastar Gas Marketing, Inc. and ARCO
                            Permian, a Unit of ARCO (filed with the Commission on
                            January 28, 1994 as Exhibit 10.18 to Vastar's
                            Registration Statement on Form S-1 (Registration No.
                            33-74536) (Commission File No. 1-13108) and incorporated
                            herein by reference)
        10.17            -- Annual Incentive Plan, as adopted by the Board of
                            Directors of ARCO on November 26, 1984, and effective on
                            that date, as amended through February 28, 1994 (filed
                            with the Commission as Exhibit 10.6 to ARCO's report on
                            Form 10-K for the year ended December 31, 1994 (File No.
                            1-1196) and incorporated herein by reference)
        10.18            -- Amendment No. 1 to the ARCO Executive Supplementary
                            Savings Plan II, as amended and effective on January 1,
                            1989 (filed with the Commission as Exhibit 10.6(b) to
                            ARCO's report on Form 10-K for the year ended December
                            31, 1989 (File No. 1-1196) and incorporated herein by
                            reference)
        10.19            -- ARCO Executive Supplementary Savings Plan II, as amended,
                            restated and effective on July 1, 1988 (filed with the
                            Commission as Exhibit 10.6 to ARCO's report on Form 10-K
                            for the year ended December 31, 1988 (File No. 1-1196)
                            and incorporated herein by reference)
        10.20            -- ARCO's 1985 Executive Long-Term Incentive Plan, as
                            adopted by the Board of Directors of ARCO on May 28,
                            1985, and as effective on that date, as amended through
                            February 28, 1994 (filed with the Commission as Exhibit
                            10.7 to ARCO's report on Form 10-K for the year ended
                            December 31, 1994 (File No. 1-1196) and incorporated
                            herein by reference)
        10.21            -- ARCO Supplementary Executive Retirement Plan, as adopted
                            by the Board of Directors of ARCO on March 26, 1990 and
                            effective on October 1, 1990 (filed with the Commission
                            as Exhibit 10.2 to ARCO's report on Form 10-K for the
                            year ended December 31, 1990 (File No. 1-1196) and
                            incorporated herein by reference)
        10.22            -- Amendment No. 1 to the ARCO Supplementary Executive
                            Retirement Plan, as effective March 22, 1993 (filed with
                            the Commission as Exhibit 10 to ARCO's report on Form
                            10-Q for the quarterly period ended June 30, 1993 (File
                            No. 1-1196) and incorporated herein by reference)
</TABLE>
    


                                      52
<PAGE>   6
   
<TABLE>
<S>                      <C>
        10.23            -- ARCO Executive Deferral Plan, as adopted by the Board of
                            Directors of ARCO on March 26, 1990 and effective on
                            October 1, 1990 (filed with the Commission as Exhibit
                            10.3 to ARCO's report on Form 10-K for the year ended
                            December 31, 1990 (File No. 1-1196) and incorporated
                            herein by reference)
        10.24            -- Amendment No. 1 to the ARCO Executive Deferral Plan, as
                            effective July 27, 1992 (filed with the Commission as
                            Exhibit 10.2(b) to ARCO's report on Form 10-K for the
                            year ended December 31, 1992 (File No. 1-1196) and
                            incorporated herein by reference)
        10.25            -- ARCO Executive Life Insurance Plan -- Summary Plan
                            Description, as in effect January 1, 1994 (filed with the
                            Commission as Exhibit 10.8 to ARCO's report on Form 10-K
                            for the year ended December 31, 1993 (File No. 1-1196)
                            and incorporated herein by reference)
        10.26            -- ARCO Executive Long-Term Disability Plan -- Summary Plan
                            Description, as in effect January 1, 1994 (filed with the
                            Commission as Exhibit 10.9 to ARCO's report on Form 10-K
                            for the year ended December 31, 1993 (File No. 1-1196)
                            and incorporated herein by reference)
        10.27            -- Form of Indemnity Agreement adopted by the Board of
                            Directors of ARCO on January 26, 1987 and executed in
                            February 1987 by ARCO and each of its directors and
                            officers, included in Exhibit A to ARCO's 1987 Proxy
                            Statement (filed with the Commission under File No.
                            1-1196) and incorporated herein by reference)
        10.28            -- ARCO Executive Medical Insurance Plan -- Summary Plan
                            Description, as in effect January 1, 1994 (filed with the
                            Commission as Exhibit 10.3 to ARCO's report on Form 10-K
                            for the year ended December 31, 1993 (File No. 1-1196)
                            and incorporated herein by reference)
        10.29            -- Vastar Policy on Financial Counseling and Individual
                            Income Tax Service, effective January 1, 1994 (filed
                            with the Commission as Exhibit 10.29 to Vastar's
                            report on Form 10-K for the year ended December 31,
                            1995 (Commission File No. 1-13108) and incorporated
                            herein by reference)(2)
        10.30            -- ARCO Policy on Financial Counseling and Individual Income
                            Tax Service, as revised and effective January 1, 1994
                            (filed with the Commission as Exhibit 10.5 to ARCO's
                            report on Form 10-K for the year ended December 31, 1994
                            (File No. 1-1196) and incorporated herein by reference)
        10.31            -- Vastar Supplementary Executive Retirement Plan (filed
                            with the Commission as Exhibit 10.34 to Vastar's report
                            on Form 10-K for the year ended December 31, 1994
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)(2)
        10.32            -- Vastar Annual Incentive Plan (filed with the Commission
                            as Exhibit 10.35 to Vastar's report on Form 10-K for the
                            year ended December 31, 1994 (Commission File No.
                            1-13108) and incorporated herein by reference)(2)
        10.33            -- Vastar Executive Long-Term Incentive Plan (filed with the
                            Commission as Exhibit 10.36 to Vastar's report on Form
                            10-K for the year ended December 31, 1994 (Commission
                            File No. 1-13108) and incorporated herein by
                            reference)(2)
        10.34            -- Vastar Executive Deferral Plan (filed with the Commission
                            as Exhibit 10.37 to Vastar's report on Form 10-K for the
                            year ended December 31, 1994 (Commission File No.
                            1-13108) and incorporated herein by reference)(2)
        10.35            -- Vastar Stock Option Plan for Outside Directors (filed
                            with the Commission as Exhibit 10.38 to Vastar's report
                            on Form 10-K for the year ended December 31, 1994
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)(2)
</TABLE>
    

                                      53
<PAGE>   7
   
<TABLE>
<S>                      <C>
        10.36            -- Vastar Deferral Plan for Outside Directors (filed with
                            the Commission as Exhibit 10.39 to Vastar's report on
                            Form 10-K for the year ended December 31, 1994
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)(2)
        10.37            -- Vastar Executive Life Insurance Plan (filed with the
                            Commission as Exhibit 10.40 to Vastar's report on Form
                            10-K for the year ended December 31, 1994 (Commission
                            File No. 1-13108) and incorporated herein by
                            reference)(2)
        10.38            -- Vastar Executive Long-Term Disability Plan (filed with
                            the Commission as Exhibit 10.41 to Vastar's report on
                            Form 10-K for the year ended December 31, 1994
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)(2)
        10.39            -- Vastar Executive Supplementary Savings Plan (filed with
                            the Commission as Exhibit 10.42 to Vastar's report on
                            Form 10-K for the year ended December 31, 1994
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)(2)
        10.39(a)         -- Amendment No. 1 to Vastar Executive Supplementary Savings
                            Plan, effective as of August 5, 1996(1)(2)
        10.40            -- Conversion Agreement, dated as of May 23, 1994, between
                            Vastar and Michael E. Wiley (filed with the Commission on
                            June 7, 1994 as Exhibit 10.43 to Amendment No. 3 to
                            Vastar's Registration Statement on Form S-1 (Registration
                            No. 33-74536) (Commission File No. 1-13108) and
                            incorporated herein by reference)(2)
        10.41            -- Conversion Agreement, dated as of May 23, 1994, between
                            Vastar and Steven J. Shapiro (filed with the Commission
                            on June 7, 1994 as Exhibit 10.44 to Amendment No. 3 to
                            Vastar's Registration Statement on Form S-1 (Registration
                            No. 33-74536) (Commission File No. 1-13108) and
                            incorporated herein by reference)(2)
        10.42            -- Conversion Agreement, dated as of May 23, 1994, between
                            Vastar and Charles D. Davidson (filed with the Commission
                            on June 7, 1994 as Exhibit 10.45 to Amendment No. 3 to
                            Vastar's Registration Statement on Form S-1 (Registration
                            No. 33-74536) (Commission File No. 1-13108) and
                            incorporated herein by reference)(2)
        10.43            -- Conversion Agreement, dated as of May 23, 1994, between
                            Vastar and Albert D. Hoppe (filed with the Commission on
                            June 7, 1994 as Exhibit 10.47 to Amendment No. 3 to
                            Vastar's Registration Statement on Form S-1 (Registration
                            No. 33-74536) (Commission File No. 1-13108) and
                            incorporated herein by reference)(2)
        10.44            -- Conversion Agreement, dated as of May 23, 1994, between
                            Vastar and Joseph P. McCoy (filed with the Commission as
                            Exhibit 10.48 to Amendment No. 3 to Vastar's Registration
                            Statement on Form S-1 (Registration No. 33-74536)
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)(2)
        10.45            -- Registration Rights Agreement, dated as of May 25, 1994,
                            between ARCO and Vastar (filed with the Commission on
                            June 7, 1994 as Exhibit 10.49 to Amendment No. 3 to
                            Vastar's Registration Statement on Form S-1 (Registration
                            No. 33-74536) (Commission File No. 1-13108) and
                            incorporated herein by reference)
        10.46            -- Vastar Retirement Plan for Outside Directors (filed with
                            the Commission as Exhibit 10.50 to Vastar's report on
                            Form 10-K for the year ended December 31, 1994
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)(2)
        10.47            -- Vastar Executive Medical Insurance Plan Summary Plan
                            Description, effective January 1, 1994 (filed with the
                            Commission as Exhibit 10.51 to Vastar's report on Form
                            10-K for the year ended December 31, 1994 (Commission
                            File No. 1-13108) and incorporated herein by
                            reference)(2)
</TABLE>
    



                                      54
<PAGE>   8
   
<TABLE>
<S>                      <C>
        10.48            -- Vastar Comprehensive Management Medical Plan Summary Plan
                            Description, effective January 1, 1994 (filed with the
                            Commission as Exhibit 10.52 to Vastar's report on Form
                            10-K for the year ended December 31, 1994 (Commission
                            File No. 1-13108) and incorporated herein by
                            reference)(2)
        10.49            -- Vastar Comprehensive Management Medical Plan, Summary of
                            Material Modifications, effective January 1, 1995 (filed
                            with the Commission as Exhibit 10 to Vastar's report on
                            Form 10-Q for the quarterly period ended June 30, 1996
                            (Commission File No. 1-13108) and incorporated herein by
                            reference)(2)
        12               -- Computation of Ratio of Earnings to Fixed Charges(1)
        21               -- List of Subsidiaries of Vastar (filed with the Commission
                            as Exhibit 21 to Vastar's report on Form 10-K for the
                            year ended December 31, 1995 (Commission File No.
                            1-13108) and incorporated herein by reference)
        23.1             -- Consent of Coopers & Lybrand L.L.P.(1)
        23.2             -- Consent of Ryder Scott Company Petroleum Engineers(1)
        27               -- Financial Data Schedule(1)
        99.1             -- Review Letter of Ryder Scott Company Petroleum
                            Engineers(1)
 
</TABLE>
    
---------------
 
(1) Filed herewith.
 
(2) Management contract or compensatory plan or arrangement required to be filed
    as an exhibit to this form pursuant to Item 14(c) of Form 10-K.
 
     Copies of exhibits will be furnished upon prepayment of 25 cents per page.
Requests should be addressed to the Corporate Secretary.
 
     (b) Reports on Form 8-K.
 
<TABLE>
<CAPTION>
 DATE OF REPORT      ITEM NO.     FINANCIAL STATEMENTS
 --------------      --------     --------------------
<S>                <C>            <C>
February 18, 1997  Items 5 and 7      None
</TABLE>


                                      55
<PAGE>   9
 
                                   SIGNATURES
 
     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused this report to be signed on
its behalf by the undersigned thereunto duly authorized.
 
                                            VASTAR RESOURCES, INC.
                                            (Registrant)
 
                                            By:     /s/ MICHAEL E. WILEY
                                              ----------------------------------
                                                       Michael E. Wiley
                                               Chairman of the Board, President
                                                              and
                                                   Chief Executive Officer
 
   
                                            Date: March 6, 1997
    
 
     Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed by the following persons on behalf of the registrant in
the capacities and on the dates indicated.

   
<TABLE>
<CAPTION>
                      SIGNATURE                                     TITLE                    DATE
                      ---------                                     -----                    ----
<S>                                                    <C>                              <C>
 
               /s/ JIMMIE D. CALLISON                  Director                          March 6, 1997
-----------------------------------------------------
                 Jimmie D. Callison
 
                 /s/ TERRY G. DALLAS                   Director                          March 6, 1997
-----------------------------------------------------
                   Terry G. Dallas
 
               /s/ CHARLES D. DAVIDSON                 Senior Vice President and         March 6, 1997
-----------------------------------------------------    Director
                 Charles D. Davidson
 
                 /s/ LINDA G. HAVARD                   Director                          March 6, 1997
-----------------------------------------------------
                   Linda G. Havard
 
                /s/ MARIE L. KNOWLES                   Director                          March 6, 1997
-----------------------------------------------------
                  Marie L. Knowles
 
                /s/ ROBERT C. LEVINE                   Director                          March 6, 1997
-----------------------------------------------------
                  Robert C. LeVine
 
                 /s/ JOSEPH P. MCCOY                   Vice President and Controller     March 6, 1997
-----------------------------------------------------
                   Joseph P. McCoy
           (principal accounting officer)
 
               /s/ WILLIAM D. SCHULTE                  Director                          March 6, 1997
-----------------------------------------------------
                 William D. Schulte
 
                /s/ STEVEN J. SHAPIRO                  Senior Vice President, Chief      March 6, 1997
-----------------------------------------------------    Financial Officer and
                  Steven J. Shapiro                      Director
            (principal financial officer)
 
                /s/ MICHAEL E. WILEY                   Chairman of the Board,            March 6, 1997
-----------------------------------------------------    President and Chief Executive
                  Michael E. Wiley                       Officer
            (principal executive officer)
</TABLE>
    


                                      56
<PAGE>   10
 
   
                                  FORM 10-K/A
 
                                   SIGNATURE
 
     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused this report to be signed on
its behalf by the undersigned thereunto duly authorized.
 
                                            VASTAR RESOURCES, INC.
                                            (Registrant)
 
                                            By:      /s/ JOSEPH P. MCCOY
                                              ----------------------------------
                                                       Joseph P. McCoy
                                                Vice President and Controller
 
Date: March 13, 1997