( ( ( ( ( Water ( injected ( into ( ( unconfined ( sand forms ) ) ( a ( stationary dome ) ) ) ) ) ) , ) and ) ( ( if ( there ( are ( confining layers ) ) ) ) ( then ( water ( ( spreads out ) horizontally ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Water)) (VP (VBD injected) (PP (IN into) (NP (NP (JJ unconfined) (NN sand) (NNS forms)) (NP (DT a) (JJ stationary) (NN dome)))))) (, ,) (CC and) (S (SBAR (IN if) (S (NP (EX there)) (VP (VBP are) (VP (VBG confining) (NP (NNS layers)))))) (ADVP (RB then)) (NP (NN water)) (VP (VBZ spreads) (PRT (RP out)) (ADVP (RB horizontally)))) (. .)))
Water injected into unconfined sand forms a stationary dome, and if there are confining layers then water spreads out horizontally.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNS sediments)) (VP (VB settle) (PRT (RP out)) (PP (IN of) (NP (NN water)))))) (, ,) (NP (PRP they)) (VP (VBP form) (NP (JJ horizontal) (NNS layers))) (. .)))
When sediments settle out of water, they form horizontal layers.