PHIVOLCS warns vs. pumice stones, volcanic debris in Batanes

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) on Tuesday has issued an advisory on the hazards posed by the presence of pumice stones and volcanic debris - from submarine eruption of a volcano in Japan - along the shores of Batanes province.

PHIVOLCS said Batanes Provincial Disaster Risk Reduction and Management Officer (PDRRMO) Dhan Esdicul reported that volcanic material have been washed onto the shores of Sitio Maydangeb, Ivana, Batanes Province.

These materials were first observed in the coves of Batan and Sabtang islands on Sunday, the 21st of November 2021.

The materials have been identified as pumice and smaller-grained volcanic ash from the recent series of submarine eruption of Fukutoku-Okanoba Volcano, which is part of the volcano islands in the Bonin Island group, Japan last August 13, 2021.

"Alternating gray and white steam and gas plumes rose to an estimated maximum height of 16 kilometers above sea level and produced an umbrella cloud at peak eruption," the PHIVOLCS reported.

"The eruption was characterized by violent explosions driven by the interaction of hot magma with seawater, generating white steam plumes and dark jets of water and rock fragments," the agency added.

During the eruption, hot and gas-rich magma rapidly cools to form pumice rocks which then float and gather on the surface forming a raft.

The eruption has also disrupted the fishing industry and port operations in Okinawa while local officials reported that a large number of fish being held in Hentona port had died from swallowing the volcanic debris.

In the Philippines, PHIVOLCS warned of the possible damage caused by floating pumice:

• Pumice may abrade boats and other structures found on the sea;
• Similarly, pumice and fine volcanic material can infiltrate and cause damage to boat engines and disruption to fishing vessels;
• Pumice and fine-grained ash material can block drainage pipes;
• Pumice rafts can obstruct sunlight, affecting the growth of marine life;
• Pumice or fine ash can also be ingested by marine animals, leading to death; there have been reports of fish kill in some parts of Japan;
• Seawater contamination is possible (e.g. from leached volcanic sulfur).

The same agency issued the following recommendations for national and local government units:

• Local government units have been advised to coordinate with the Office of Civil Defense (OCD) to enlist the Philippine Coast Guard (PCG) in warning sea vehicles on the presence of pumice rafts as these pose hazards to marine vessels and aquatic activities.
• LGUs should seek help from the PCG to implement containment measures such as the use of spill boom, use of nets/trawls, scooping via shovel loaders, boats;
• Marine agencies such as Bureau of Fisheries and Aquatic Resources (BFAR) are enjoined to test for seawater contamination around affected communities of Batanes Province;
• LGUs should mobilize barangay officials and their units, volunteers and civil society to help monitor the beaches and note important information such as locality of occurrences, thicknesses and general areal coverage of volcanic deposits and date and time of observation in the coastlines;
• LGUs should look for a place to temporarily collect the pumice and explore long-term plans for proper disposal or use;
• LGUs should issue warnings and advisories against swimming in coasts with floating pumice.

"People are reminded to avoid swimming and other beach activities for the meantime as the pumice rafts reduce visibility when swimming underneath these and may cause abrasion injuries. This also safeguards against ingestion of seawater with potentially harmful substances (such as sulfur and very fine ash) that may have been brought by the pumice rafts," the PHIVOLCS announced.

Pumice and ash materials should be collected in rice sacks by personnel using Personal Protective Equipment or PPE and LGUs are advised to identify storage location.

"LGUs may mobilize barangay officials, volunteers to monitor and document the location, time and date of observation of the pumice rafts. When able, photographs, visual estimate measurements such as extent, and thickness may be collected," PHIVOLCS said.

"LGUs are advised to ensure that communication systems are in place. During these events, rumors are easily spread that may cause panic. Please avoid sharing messages from unconfirmed and unreliable sources," the agency underscored. -- BAP, GMA News