23 November 2021

 

What is happening in Batanes and vicinity?

At 07:45 AM Philippine Standard Time (PST) of 23 November 2021(Tuesday), the Batanes Provincial Disaster Risk Reduction and Management Officer (PDRRMO), Mr. Dhan Esdicul, reported to the DOST-PHIVOLCS Batanes Seismic Station that volcanic material have been washed onto the shores of Sitio Maydangeb, Ivana, Batanes Province (Figure1). This was first noticed in coves of Batan and Sabtang islands on 21 November 2021 (Sunday).

 

What are and where did these volcanic materials come from?

These materials are pumice and smaller-grained volcanic ash washed onto some of the shores of islands of the Province of Batanes generated by the recent eruption of Fukutoku-Okanoba Volcano. Fukutoku-Okanoba is a submarine volcano that is part of the Volcano Islands in the Bonin Island group, Japan. It is located five kilometers northeast of the island of South Iwo Jima and more than two thousand kilometers northeast of Batanes and Aparri, Cagayan. The pumice and volcanic ash were carried by ocean currents to the shores of Japan and the Philippines.

 

The Recent Eruption of Fukutoku-Okanoba Volcano

A series of submarine eruptions of Fukutoku-Okanoba Volcano was documented by the Japan Coast Guard on 13 August 2021 during a flight observation that confirmed the eruption as well as the height of the eruption plumes. 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 explosions quickly created a new cone that breached the surface (Figure 2). 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.

 

 

Satellite images from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) shows a steam and gas plume being dispersed to the west of the volcano (Figure 3).

 

 

 

 

The massive underwater eruption ejected tens of millions of cubic meters of pumice and other finer volcanic debris, or “pumice rafts”, which started washing up along coastlines of Okinawa Prefecture, Japan. Pumice rafts are floating masses of buoyant porous rocks resulting from submarine volcanic eruption. 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 (Figures 4 and 5).

 

The eruption also caused huge damages and disruption to the fishing industry, fishing vessels and port operations in Okinawa. Local officials reported that a large number of fish being held in Hentona port had died from swallowing the volcanic debris.

 

What are the hazards and possible damages caused by floating pumice?

1. Pumice may abrade boats and other structures found on the sea;

2. Similarly, pumice and fine volcanic material can infiltrate and cause damage to boat engines and disruption to fishing vessels;

3. Pumice and fine-grained ash material can block drainage pipes;

4. Pumice rafts can obstruct sunlight, affecting the growth of marine life;

5. 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;

6. Seawater contamination is possible (e.g. from leached volcanic sulfur).

 

What should be the immediate actions of national and local government units (LGUs)?

1. LGUs are 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.

2. 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;

3. Marine agencies such as Bureau of Fisheries and Aquatic Resources (BFAR) are enjoined to test for seawater contamination around affected communities of Batanes Province;

4. 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;

5. LGUs should look for a place to temporarily collect the pumice and explore long-term plans for proper disposal or use;

6. LGUs should issue warnings and advisories against swimming in coasts with floating pumice.

 

What should be done by the affected communities?

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 collected pumice and ash materials should be stored properly in containers or rice sacks for easier collection and transport. LGUs are advised to identify temporary storage locations of pumice and ash collected as long-term proper disposal is being explored.

 

As the pumice dries out, it becomes easy to crumble and may be reduced to finer dust particles when hauled or mobilized. Use of Personal Protective Equipment (PPE) such 6 as goggles and facemask, especially for personnel directly handling the hauling, transport and storage of the volcanic materials is advised.

 

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.

 

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.

 

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