That area does have that size quake occasionally - here is a list of quakes 5.5+ at your location since 1973:
CAT YEAR MO DA ORIG TIME LAT LONG DEP MAGNITUDE IEFM DTSVNWG DIST
NFPO km
TFS

PDE 1973 07 03 035953.70 19.10 -101.83 125 5.60 mb GS .F.. ....... 150
PDE 1973 07 16 181257.50 17.32 -100.68 44 6.20 UKPAS .... ....... 82
PDE 1975 02 22 004721.70 17.36 -100.48 40 5.80 Ms GS .... ....... 89
PDE 1975 11 15 152830.40 18.23 -102.18 33 6.10 UKPAS .F.. ....... 127
PDE 1976 02 01 111457.30 17.17 -100.19 52 5.70 mb GS .... ....... 125
PDE 1976 06 07 142639.10 17.40 -100.64 45 6.70 UKPAS .C.. ....... 76
PDE 1976 09 19 205805.10 18.22 -100.47 55 5.60 mb GS .F.. ....... 61
PDE 1978 03 19 013914 17.03 -99.74 36 6.60 UKPAS .C.. ....... 171
PDE 1978 07 05 201516.30 18.49 -100.01 62 5.60 mb GS .F.. ....... 117
PDE 1978 09 29 162141 18.61 -102.26 96 5.50 mb GS .... ....... 149
PDE 1979 01 26 100432 17.41 -100.88 41 6.90 UKBRK .F.. ....... 66
PDE 1979 01 26 171044.10 17.55 -100.99 39 5.70 UKBRK .F.. ....... 49
PDE 1979 03 14 110716.30 17.81 -101.28 49 7.60 Ms GS .C.. ....... 35
PDE 1979 03 14 120124.80 17.95 -101.28 52 5.50 mb GS .F.. ....... 30
PDE 1981 07 26 051422.69 18.22 -101.89 29 5.50 MsBRK .F.. ....... 97
PDE 1981 10 25 032215.57 18.05 -102.08 33 7.40 MsBRK .CFG ....... 114
PDE 1983 12 08 102156.57 18.55 -102.58 68 5.50 mb GS .F.G ....... 177
PDE 1985 09 19 131747.35 18.19 -102.53 27 8.10 Ms GS 9CFG .TS...M 163
PDE 1985 09 21 013713.47 17.80 -101.65 30 7.60 Ms GS 6CFG .T..... 71
PDE 1985 10 29 150227.84 18.16 -102.55 38 5.60 mb GS .C.G ....... 164
PDE 1986 05 05 054637.48 18.16 -102.66 37 5.60 mb GS .F.G ....... 175
PDE 1988 02 08 135133.95 17.74 -100.96 58 5.80 MsBRK .F.G ....... 29
PDE 1990 05 31 073527.01 17.26 -100.71 22 6.00 MsBRK 4FFG ....... 87
PDE 1993 03 31 101814.25 17.32 -100.91 29 5.50 MwHRV .F.G ....... 75
PDE 1994 05 23 014142.29 18.17 -100.53 55 6.30 MwGS .FFG ....... 53
PDE 1994 12 10 161738.51 18.14 -101.38 48 6.60 mb GS .DFG ....... 43
PDE 1996 01 25 124508.41 18.51 -102.13 76 5.50 MwHRV ...G ....... 131
PDE 1996 04 23 065335.39 17.28 -101.36 33 5.60 MwHRV ...G ....... 88
PDE 1996 07 15 212334.08 17.60 -100.96 18 6.80 MwGS .F.G ....... 44
PDE 1997 01 11 202826.02 18.22 -102.76 33 7.20 MwGS .CFG ....... 187
PDE 1997 01 16 214107.07 18.10 -102.68 28 5.60 mb GS ...G ....... 177
PDE 1997 05 22 075053.52 18.68 -101.60 70 6.50 MwGS .DFG ....... 98
PDE 1998 04 20 225914.77 18.52 -101.20 67 6.00 MwGS .FFG ....... 61
PDE 1998 07 11 052113.44 17.39 -101.35 33 5.50 MwHRV .F.G ....... 76
PDE 1998 07 12 081128.18 16.95 -100.29 33 5.50 MwHRV ...G ....... 137
PDE 1999 06 21 174304.52 18.32 -101.54 68 6.30 MwHRV .DFG ....... 67
PDE-W 1999 12 29 051946.91 18.24 -101.43 69 6.10 mb GS .C.G ....... 53