The Unusual Meaning and Origin of the Idiom 'Tip of the Iceberg'

Meaning and Origin of the Idiom 'Tip of the Iceberg'
Like many idioms, 'tip of the iceberg' has become part of our speech. But, for those of you who don't have a clear idea, Penlighten deciphers its meaning for a good understanding.
It's Where the Titanic Collided!
It is said that the doomed sinking of RMS Titanic in 1912 was due to an unfortunate collision with an iceberg. According to a theory, misjudgment of the size of that iceberg on part of the officer in charge of the ship led to its fatal end.
We wonder if it is the Titanic incident that gave birth to the idiom 'tip of the iceberg.' Though one cannot pinpoint the exact origin of the idiom, the first known use of it was recorded in 1969.
Origin
It must have been an iceberg and not the ship that became the inspiration for the idiom. It alludes the structure of an iceberg. An iceberg is a huge broken piece of a freshwater glacier, which floats freely in open water. Only one-seventh to one-tenth part of the iceberg is seen floating above water. Over 90% of volume and mass of the iceberg is in a submerged state. It is always difficult to judge the size and shape of the underwater portion of the iceberg by looking at just the tip floating above water. Many ships, such as RMS Titanic, have suffered a fatal loss due to this. This misleading structure of the iceberg must have led to the idiom-tip of the iceberg.
Meaning
According to Merriam-Webster, the idiom means "the earliest, most obvious, or most superficial manifestation of some phenomenon." The phenomenon, like the submerged part of the iceberg, is always larger is size that one can perceive. What is perceived is just the trivial appearance.

The idiom is used to refer to a situation or problem, which is anticipated as small in effect, but its larger part is hidden. One may not able to take in the whole problem or the situation, just like it is harder to guess the size of the underwater portion of the iceberg. The tip is just a small part of the bigger problem. The idiom has a negative connotation to it as it is used to warn that there is more to the situation or the problem than what is visible. The expression can be used to describe a person who difficult to figure out as well.
Examples of the Idiom
► That one article addressing the current issue, which was published in the newspaper, is just a tip of the iceberg. There are more such articles to come.

► When our company laid off few people one month back, it was just the tip of the iceberg. Since then, over 40 people have been laid off.

► The detectives finding one clue is just a tip of the iceberg. The mystery of the murder is yet to be solved.

► The information a person gathers in his lifetime is just a tip of the iceberg, compared to the information that in available in the world.

► The number of rape cases that are brought to court is just the tip of the iceberg, there are many more to uncover.
Tip of the Iceberg Synonyms
These tip of the iceberg synonyms can be used in sentences to constitute the same meaning.

◆ On the surface
◆ One-dimensional
◆ On the table/Under the table
◆ There is more than meets the eye
◆ Read between the lines
◆ Scratch the surface
◆ One drop of water out of an ocean
◆ Leading edge
◆ One speck of sand out of the entire desert
◆ A chip out of the teacup