Anomalous zone of chlorophyll as precursor of Ambon-Seram earthquake September 26th, 2019

Earthquake precursors in several recent studies examine anomalous changes that occur inland, oceans, atmosphere, and ionosphere before an earthquake occurs. Microwave technology and optical sensors on satellites can now monitor changes in land, oceans, atmosphere, and ionosphere for related natural hazards. The purpose of this study was to examine changes in the Chl-a anomaly as an earthquake precursor using remote sensing data from sea waters located near the epicenter of the Ambon-Seram earthquake (26 September 2019). The results of the analysis showed a loss of concentration of Chlorophyll-a (Chl-a) around the study site which was then called the anomaly zone. The anomaly zone which is an earthquake precursor that occurs is thought to be due to cloud cover or other influences. The measurement of the effect of chlorophyll concentration associated with daily earthquake events continuously has limitations due to this matter. The ocean area adjacent to the earthquake epicenter provides strong evidence of increased Chl-a concentrations. The concentration of Chl-a experienced a drastic increase after the September 2019 earthquake of 28.31 mg m⁻³ due to changes in sea surface temperature. This is related to pressure changes in the in situ modified epicentral region, thermal structure of water, and increased upwelling, water nutrients. The increase in Chl-a concentration also showed an increase in Surface Latent Heat Flux (SLHF) which increased significantly before the earthquake. At the same time, the K-Index and Total-Totals Index dropped drastically by 24K and 15K.