On Indonesia’s recent natural disasters: Quake jolts Malang and other regions; tropical cyclone may trigger further floods, meteorology agency warns

JAKARTA, INDONESIA — A tropical cyclone — defined as a low-pressure system formed over warm tropical waters, with a maximum wind speed of 34 knots — could trigger more severe natural disasters such as the recent floods in East Nusa Tenggara and West Nusa Tenggara, Indonesia’s meteorological body warned.

A 5.5-magnitude quake rocked West Nusa Tenggara at 5.36 pm in West Sumbawa, West Nusa Tenggara. The tremor did not trigger a tsunami potential, based on official data.

A 5.1-magnitude tremor, later revised to 4.9-magnitude, shook Banten province on Wednesday afternoon (14 Apr). The quake was also felt in Jakarta and Sukabumi.

Previously, a 5.1-magnitude tremor jolted East Java’s Malang on 10 Apr. The effect of the quake also spread to other cities in East Java, as well as the islands of Bali and Lombok. Ripples from the quake were also felt as far as Central Java.

Indonesia is vulnerable to quakes, as it sits on the Ring of Fire — a string of active volcanoes around the Pacific Ocean.

In January this year alone, the meteorology agency recorded 646 quakes with various depths and magnitudes.

Aftershocks in Malang also felt in other cities

There were eight aftershocks from 10 Apr to 11 Apr as of 7.25 am in Malang, said the head of the Earthquake Centre at the Meteorology, Climatology and Geophysics Agency (BMKG), Bambang Setiyo Prayitno.

“The magnitude stood between 3.1 and 5.3,” he explained in an official statement, as cited in Republika.

Eight died and 39 were injured due to the quake, which was also felt in other cities such as Surabaya, Trenggalek, Tulungagung, and Lumajang.

“Several aftershocks were felt in Trenggalek, my sister said. But I felt the first quake here,” a Surabaya resident told TOC on 10 Apr.

The tremor also damaged 179 public facilities and thousands of houses, BMKG chief Dwikorita Karnawati said, citing data from the National Disaster Mitigation Agency (BNPB).

Based on BMKG’s evaluation, the resulting damage caused to buildings were tied to their poor structures, which did not meet quake-proof requirements.

Also, much of the affected property did not have column structures at the corners, she elaborated.

Other causing factors are the state of rock and soil as the damages were mostly found in regions with lava and alluvium sediments, she added.

A tropical cyclone predicted next

A tropical cyclone brings the possibility of rain, ranging from medium to heavy, and is accompanied by thunderstorms and strong winds. Such cyclones can also trigger high sea waves.

The national disaster mitigation body warned that 30 provinces had to anticipate the potential of the seeds of tropical cyclone 94W.

Jakarta’s regional disaster mitigation agency also issued a similar warning, saying that the potential of extreme weather would hit the capital from 15 Apr to 16 Apr.

The body also alerted Jakarta residents to the potential consequences of the tropical cyclone such as floods, landslides, slippery roads, and thunderstorms.

The tropical cyclone Seroja is linked to the flood in East Nusa Tenggara that took place recently.

The BMKG issued an early warning of a tropical cyclone on 2 Apr.

Several factors play a role in forming the tropical cyclone Seroja, such as a warmer temperature of the sea surface on the Indian Ocean, reaching more than 26.5 – 29 degree Celsius.

“A 2 degree Celsius rise is significant in influencing weather conditions,” Dwikorita said.