Surabaya: Bromo Tengger Semeru National Park

Mount Bromo is an active volcano in Tengger National Park, located in East Java.   At, 7, 641 feet, it is not the highest massif but it is the most well-known and the most visited.  Mount Bromo is named after Brahma, the Hindu creator god.  This stratovolcano is located in the middle of the "Sea of Sand" comprised of dark gray ashes from previous eruptions, the most recent one taking place in January 2011.

To begin our trek to see the sunrise over Mount Bromo and Mount Semeru from the viewpoint on Mount Penanjakan, we awoke at 3:00AM and took a 45 minute jeep ride across the Sea of Sand.  Upon arriving at the viewing platform we were able to observe several constellations as we waited for the sunrise.  We spotted Orion the Hunter, one of the most recognizable constellations visible throughout the world.  At around 5:15AM, the sun began to peak out from the horizon and illuminated the Tengger massif.  From our viewpoint we were able to see the sulphuric gases emerging from both Bromo and Semeru.

Sunrise over Mount Bromo

Semeru volcano eruption

In the afternoon, we hiked 3 kilometers across the "Sea of Sand" and climbed up 150 steps to get an up-close view of the crater rim and the sulphuric gases.  

"Sea of Sand"

Science Connection:  Mount Bromo is an example of a stratovolcano.  During the hike we collected various samples of volcanic ash and cooled lava.  We also observed the erosion from lava flows along the rock formation.  Students can study the samples and make observations first hand about the properties of a stratovolcano.   We also noticed that the vegetation changed as we increased in elevation from Surabaya to the mountain village near Mount Bromo.  From photographs and knowledge gained in our environment unit, students can observe the alpine trees, low shrubs, and flowering plants like edelweiss and how they've all adapted to this high altitude environment.   

Edelweiss - found in Alpine biomes

Erosion from lava flow river

Evergreen tree

Math Connection: 

Mount Bromo is 2,329 metres (7,641 ft) it is not the highest peak of the massif, but is the most well known. For the scaling project for the upcoming school year based on the height we start thinking about the right scale to model the volcano. As we try our model to be not larger than 2 ft a possible scale factor could be 1/4000 which would create a model that is close to the height of 1.9 feet. However we also need to consider the width and the length of the volcano and how would that translate into the new model with the given scale factor. 

Recorded eruptions of Bromo volcano:  1804, 1815, 1820, 1822, 1825, 1829, 1830, 1835, 1842, 1843, 1844, 1856, 1857, 1858, 1858, 1859, 1860, 1865, 1865, 1866, 1867-68, 1877, 1885, 1885-86, 1886, 1886-87, 1888(?), 1890, 1893, 1896, 1906-07, 1907, 1907-08, 1909, 1910, 1915-16, 1921, 1922, 1928, 1930, 1935, 1939, 1940, 1948, 1950, 1955, 1956, 1972, 1980, 1983, 1984, 1995, 2000, 2004 and most recently in 2010. The group that will be responsible to create the model for Mount Bromo will also analyze and graph this data to find the slope, the correlation coefficient and the equation of the line that fits the the frequency.

Hiking up to the crater of Bromo