The downfall of a mighty city's leaders is likened to the tragic sinking of a great ship, sending ripples of panic far beyond the immediate disaster. As the crisis strikes, the desperate cries of the ship's captains and leaders ring out [מצודת דוד, מלבי״ם, רד״ק]. The sheer terror of this cry causes a massive shockwave, making the surrounding areas tremble and shake in fear [מצודת ציון].
The exact nature of these shaken surroundings is viewed from several angles. The primary approach among commentators is that the panic strikes the open spaces and nearby cities closest to the sinking ship [רש״י, רד״ק, מצודת דוד]. More specifically, this refers to the houses built outside the city walls along the coast, which appear as though they were pushed out from the main city [מצודת ציון]. By describing the land-based outskirts of Tyre violently shaking from a disaster occurring out at sea, the imagery uses deliberate exaggeration to capture the overwhelming force of the crisis [רד״ק].
Others broaden the scope of this impact beyond the nearby land. Some explain that the trembling reaches the seashores themselves, meaning the city's cry is heard everywhere without exception [ביאור שטיינזלץ]. Alternatively, the imagery extends further into the maritime world, representing all the other ships and islands scattered across the water. In this view, these surrounding vessels and islands act as the open suburbs to the once-mighty ship of Tyre, and they too shake as it goes down [מלבי״ם].