CREATE TABLE table_19621 ("Explosion" CLOB, "Location" CLOB, "Date" CLOB, "Yield  ( approximate ) " CLOB, "Altitude  ( km ) " CLOB, "Nation of Origin" CLOB)

What was the altitude of the event on 1962-07-09?
SELECT "Altitude (km)" FROM table_19621 WHERE "Date" = '1962-07-09'
SELECT "Altitude (km)" FROM "table_19621" WHERE "Date" = '1962-07-09'