What are shield volcanoes characterized by?

Shield volcanoes are characterized by broad, gently sloping shapes that are formed primarily by the low-viscosity lava that they erupt. This type of lava is fluid and can travel great distances from the vent, leading to the gradual build-up of wide, expansive shields that resemble a warrior's shield lying on the ground. The gentle slopes result from the ability of the lava to flow easily, allowing multiple layers to accumulate over time without creating steep angles or towering peaks.

In contrast, other types of volcanoes are defined by different characteristics. For instance, those with steep, conical shapes and explosive eruptions typically represent stratovolcanoes, which are formed from a mixture of lava flows and explosive materials. Narrow bases and high peaks are also indicative of these stratovolcano types rather than shield volcanoes. The option describing a complete absence of lava flow does not apply to shield volcanoes, as they are defined specifically by their lava eruptions. Thus, the distinctive broad, gently sloping shape formed by fluid lava flows sets shield volcanoes apart clearly from other volcano types.