How to fix "Segmentation fault" in fortran program - fortran

Question

I wrote this program that reads daily gridded climate model data (6 variables) from a file and uses it in further calculations. When running the pgm for a relatively short period (e.g. 5 years) it works fine, but when I want to run it for the required 30 year period I get a "Segmentation fault".
System description: Lenovo Thinkpad with Core i7 vPro with Windows 10 Pro
Program run in Fedora (64-bit) inside Oracle VM VirtualBox
After commenting out everything and checking section-by-section I found that:
everything works fine for 30 years as long as it reads 4 variables only
as soon as the 5th or 6th variable is added, the problem creeps in
alternatively, I can run it with all 6 variables but then it only works for a shorter analysis period (e.g. 22 years)
So the problem might lie with:
the statement: recl=AX*AY*4 which I borrowed from another pgm, yet changing the 4 doesn't fix it
the system I'm running the pgm on
I have tried the "ulimit -s unlimited" command suggested elsewhere, but only get the response "cannot modify limit: Operation not permitted".
File = par_query.h
integer AX,AY,startyr,endyr,AT
character pperiod*9,GCM*4
parameter(AX=162,AY=162) ! dim of GCM array
parameter(startyr=1961,endyr=1990,AT=endyr-startyr+1,
& pperiod="1961_1990")
parameter(GCM='ukmo')
File = query.f
program query
!# A FORTRAN program that reads global climate model (GCM) data to
!# be used in further calculations
!# uses parameter file: par_query.h
!# compile as: gfortran -c -mcmodel=large query.f
!# gfortran query.o
!# then run: ./a.out
! Declarations ***************************************************
implicit none
include 'par_query.h' ! parameter file
integer :: i,j,k,m,n,nn,leapa,leapb,leapc,leapn,rec1,rec2,rec3,
& rec4,rec5,rec6
integer, dimension(12) :: mdays
real :: ydays,nyears
real, dimension(AX,AY,31,12,AT) :: tmax_d,tmin_d,rain_d,rhmax_d,
& rhmin_d,u10_d
character :: ipath*43,fname1*5,fname2*3,nname*14,yyear*4,mmonth*2,
& ext1*4
! Data statements and defining characters ************************
data mdays/31,28,31,30,31,30,31,31,30,31,30,31/ ! Days in month
ydays=365. ! Days in year
nyears=real(AT) ! Analysis period (in years)
ipath="/run/media/stephan/SS_Elements/CCAM_africa/" ! Path to
! input data directory
fname1="ccam_" ! Folder where data is located #1
fname2="_b/" ! Folder where data is located #2
nname="ccam_africa_b." ! Input filename (generic part)
ext1=".dat"
leapa=0
leapb=0
leapc=0
leapn=0
! Read daily data from GCM ***************************************
do n=startyr,endyr ! Start looping through years --------------
write(yyear,'(i4.4)')n
nn=n-startyr+1
! Test for leap years
leapa=mod(n,4)
leapb=mod(n,100)
leapc=mod(n,400)
if (leapa==0) then
if (leapb==0) then
if (leapc==0) then
leapn=1
else
leapn=0
endif
else
leapn=1
endif
else
leapn=0
endif
if (leapn==1) then
mdays(2)=29
ydays=366.
else
mdays(2)=28
ydays=365.
endif
do m=1,12 ! Start looping through months --------------------
write(mmonth,'(i2.2)')m
! Reading daily data from file
print*,"Reading data for ",n,mmonth
open(101,file=ipath//fname1//GCM//fname2//nname//GCM//"."//
& yyear//mmonth//ext1,access='direct',recl=AX*AY*4)
do k=1,mdays(m) ! Start looping through days --------------
rec1=(k-1)*6+1
rec2=(k-1)*6+2
rec3=(k-1)*6+3
rec4=(k-1)*6+4
rec5=(k-1)*6+5
rec6=(k-1)*6+6
read(101,rec=rec1)((tmax_d(i,j,k,m,nn),i=1,AX),j=1,AY)
read(101,rec=rec2)((tmin_d(i,j,k,m,nn),i=1,AX),j=1,AY)
read(101,rec=rec3)((rain_d(i,j,k,m,nn),i=1,AX),j=1,AY)
read(101,rec=rec4)((rhmax_d(i,j,k,m,nn),i=1,AX),j=1,AY)
read(101,rec=rec5)((rhmin_d(i,j,k,m,nn),i=1,AX),j=1,AY)
read(101,rec=rec6)((u10_d(i,j,k,m,nn),i=1,AX),j=1,AY)
enddo ! k-loop (days) ends --------------------------------
close(101)
enddo ! m-loop (months) ends --------------------------------
enddo ! n-loop (years) ends -----------------------------------
end program query