▁northern ▁most ▁and ▁southern ▁most ▁con es ▁is ▁about ▁ 3 . 5 ▁kilom eters . ▁ ▁Cl os ely ▁related ▁to ▁the ▁Four ▁C rat ers ▁la va ▁field ▁is ▁Cra ck - in - the - Gr ound ▁located ▁at ▁the ▁south west ▁corner ▁of ▁the ▁field . ▁The ▁er u ptions ▁from ▁the ▁field ▁were ▁accompanied ▁by ▁a ▁slight ▁s inking ▁of ▁the ▁older ▁rock ▁surface . ▁This ▁shall ow , ▁gra ben - like ▁sink ▁is ▁about ▁ 3 ▁kilom eters ▁wide ▁and ▁extends ▁to ▁the ▁south ▁into ▁an ▁old ▁lake ▁bas in . ▁Cra ck - in - the - Gr ound ▁marks ▁the ▁western ▁edge ▁of ▁this ▁small , ▁vol cano - te ct onic ▁de pression ▁and ▁is ▁nearly ▁ 9 ▁meters ▁deep ▁and ▁over ▁a ▁meter ▁wide . ▁The ▁crack ▁is ▁the ▁result ▁of ▁a ▁t ension ▁f ract ure ▁along ▁a ▁h ing eline ▁produced ▁by ▁the ▁dra pping ▁of ▁Green ▁Mountain ▁la va ▁flows ▁over ▁the ▁edge ▁of ▁up th rown ▁side ▁of ▁the ▁conce aled ▁fault ▁zone . ▁ ▁References ▁ ▁( arch ived ) ▁ ▁Further ▁reading ▁▁▁▁▁▁ ▁Category : Vol can ic ▁fields ▁of ▁Oregon ▁Category : Land forms ▁of ▁Lake ▁County , ▁Oregon ▁Category : Vol can ic ▁fields ▁of ▁the ▁Great ▁Bas in ▁section ▁Category : D esch utes ▁National ▁Forest ▁Category : L ava ▁fields <0x0A> </s> ▁Lord ▁Richard ▁Buck ley ▁( born ▁Richard ▁My r le ▁Buck ley ; ▁April ▁ 5 , ▁ 1 9