add a trigger on table 2 which will insert a row in table 1
CREATE TRIGGER <Schema_Name, sysname, Schema_Name>.<Trigger_Name, sysname, Trigger_Name>
ON <Schema_Name, sysname, Schema_Name>.<Table_Name, sysname, Table_Name>
AFTER <Data_Modification_Statements, , INSERT>
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
-- Insert statements for trigger here
END