Which of the following statements with reference to stratovolcanoes is/are correct? 1. Stratovolcanoes are tall, steep cones built of layers of felsic lava and volcanic ash. 2. They can erupt explosively as felsic lavas from stratovolcanoes hold large amounts of gas under high pressure. Select the answer using the code given below.

Stratovolcanoes, also known as composite volcanoes, are characterized by their tall, steep conical profiles built from alternating layers of hardened lava, volcanic ash, and tephra [5]. These volcanoes typically erupt felsic to intermediate magmas, such as andesite, dacite, and rhyolite, which have high silica content and high viscosity [3]. Statement 1 is correct as these layers of lava and ash (strata) give the volcano its name and steep shape [2]. Statement 2 is also correct because the high viscosity of felsic lavas prevents gas from escaping easily, allowing pressure to build up significantly [4]. When this pressure is released, it results in violent, explosive eruptions that eject large quantities of pyroclastic material [2]. This distinguishes them from shield volcanoes, which erupt low-viscosity basaltic lava and are generally non-explosive [4].

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 11: Volcanism > Composite Type Volcano (Stratovolcano) > p. 140
2. [3] https://en.wikipedia.org/wiki/Stratovolcano
3. [5] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 8: Natural Hazards and Disaster Management > 8.4 Environment and Ecology > p. 11
4. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 11: Volcanism > Andesitic Or Acidic Or Composite Or Stratovolcanic Lava > p. 139
5. [4] https://www.bgs.ac.uk/discovering-geology/earth-hazards/volcanoes/how-volcanoes-form/