How are we, as seekers of truth from a spiritual perspective, to understand an event such as the one above? The link below is to a Steiner lecture where he gives his view on the origin of earthquakes:

https://southerncrossreview.org/69/steiner-earthquakes.htm

Points discussed —

• The difference between Ahriman (Faust’s Mephistopheles) and Lucifer. 
• How Lucifer’s intervention in human affairs allowed for personal freedom, but at the cost of creating the possibility for evil.
• Individual versus collective karma
• How when the Christ in the body of Jesus bled from the hands on the cross at Golgotha, it changed the sorry state of affairs that had been existing for those human souls in Spiritland between death and a new birth. Ahriman had been gaining power there and had turned it into the Realm of the Shades. But the Christ event banished him and confined his power to Earth, to the land of the living. Souls in Spiritland were able to see each other again. But the battle against Ahriman continues here.
• The different strata below the Earth: Mineral Earth, Water Earth, Vapor Earth, Form Stratum, Fertile Earth, Fire Earth. It is from Fire Earth where Ahriman has his base of operations and where earthquakes have their origin.
• Earthquakes and other great natural catastrophes are remnants or reminders of the great Atlantean catastrophe, the flood that sank that continent, which happened as a result of collective human karma. Thus we mustn’t think that, for example the people of Syria and Turkey, are suffering as a result of their nationalistic karma (even though such karmic divisions do exist), but rather they happen to be in the place where a karmic event that began on Atlantis, is still having its ‘aftershocks,’ as it were. This event involves the entire human race, we all share in this guilt.
• Steiner says, “our compassion for the victims of such catastrophes will be all the greater, for our knowledge tells us that there is a collective karma of humanity from which the individual members have to suffer, that just as such happenings are brought about by humanity as one whole, so too must humanity be answerable for them; we must regard such a destiny as our own and help not only out of a spontaneous impulse but because we know that we are involved in the karma of humanity and share the guilt incurred!”
• Individuals thus sometimes are guiltless but undergo terrible calamities because they get swept up into collective karma. But, and this is the important point, if they are truly guiltless they will be compensated in future incarnations. Nothing is random, nothing is forgotten, all accounts are balanced.
• Why adepts or psychics versed in spiritual science who can foresee events like this coming and don’t warn people. The reason being that as terrible as these natural disasters are, they relieve karmic pressure, and if for example they had warned everyone to flee and the disaster had been averted, it would be forced to happen again elsewhere; it would really only be postponing it.

Further Reading

Anthroposophy.eu — Earth’s Inner Layers

The Interior of the Earth: An Esoteric Study of the Subterranean Spheres

 Rosicrucian Training — Interior of the Earth — Earthquakes and Volcanoes