The Seahawks' third-down defense has been in the spotlight recently for obvious reasons. That wasn't specifically a problem Sunday against the Chiefs; Seattle's defensive problems ran across all downs. We have three charts below. The first one breaks down the third-down defense this season. The second and third charts list all plays against Seattle longer than 19 yards.
First, the third-down chart (note that opponents have converted 7-10 times on third-and-7; that includes 2-2 by the Chiefs, for passes of 16 and 19 yards):
The second chart takes a game-by-game look at big plays allowed. There have been five plays of 20-24 yards, 12 plays of 25-39 yards and seven plays of 40-95 yards. You can see that six of those 40-plus plays have come in the last four games (after Seattle allowed only one in the first three games). You can see there have been 24 plays of 20-plus yards against Seattle's defense this season.