Merapi volcano (Java, Indonesia): increasing earthquakes - an ominous sign of upcoming dangerous eruption?

Over the past several days, seismic activity from the Merapi volcano – Indonesia's most active – has been increasing significantly, suggesting that a more intense phase of volcanic activity is on its way.
Indonesia's volcanologists recorded a record number of volcanic earthquakes under the volcano, namely 720 quakes yesterday and 680 the day before, both of which represented new records in recent months. The average for the month of November had been around 30 before these record figures. It is particularly worrying that many of the newly detected tremors may be caused by rock-breaking magma which has the power to create new magma conduits or widen existing ones inside the volcano itself. These tremors are known as volcano-tectonic quakes and can be quite dangerous.
In response to the latest activity, local authorities have extended the existing state of emergency for Merapi by one more month. As many as 240 people, recently evacuated from homes lying in particularly dangerous places around the slopes of the volcano, will need to be more patient before being allowed to return home.

It is probably only a question of time before fresh magma once again emerges from the summit vent. The big question is when and how much. If the magma's volume is large enough to create a dome that's bigger than the capacity of the crater, this will almost certainly generate extremely dangerous and potentially large glowing avalanches, known as pyroclastic flows. These turbulent hot flows can destroy everything in their path and can devastate large areas of lower-lying terrain, especially around the region's river valleys at a distance of 10-20 km from the volcano.

Merapi is one of the most active volcanoes in the world and has been producing such flows, often large ones, very frequently. This and the fact that its slopes are densely inhabited makes it one of the deadliest volcanoes whose pyroclastic flows have repeatedly claimed many victims.