In this paper, we used detailed bathymetry, earthquake distribution and focal mechanisms to study the phenomenon of active westward exten sion of the Okinawa trough in the northern Taiwan area. We found a dis tinguishable subsiding and collapsing area on the continental shelf edge and the continental slope on the northern side of the Okinawa trough. This area extends westwards to at least 121.5°E and includes several morpho logical units related to the existence and formation of three major canyons. The canyons and the morphological units are still evolving through the sedi ment transport and through the subsidence and collapse of material due to the formation of the Okinawa trough. According to the degree of develop ment, we found that these morphological units have developed from the east to the west. There are two parallel E-W trending central graben at the westernmost part of the Okinawa trough, with each corresponding to a narrow shallow seismic belt. The widths of the central graben are 10-15 km. There is geophysical and geological evidence that the formation of these central graben has been extended westwards to the onland area of Taiwan. Focal mechanisms of earthquakes and the topographic features show that the formation of the Okinawa trough is associated with the down-dip ex tensional stress along the subducting slab of the Philippine Sea plate, and most of northern Taiwan and all the northeastern offshore area of Taiwan are under tensional stress. New portions of the Okinawa trough have been forming across the whole width at its western end through subsidence in the continental shelf, the continental slope and the traditionally recognized area of the Okinawa trough in the northeastern Taiwan area, to make the Okinawa trough develop gradually and extend westwards.

No abstract

No abstract

No abstract

Because the nature of numerical information is intuitive and comprehensible, it has been widely used to form a basis for decision making, yet numerical information based on historical principle does not reflect messages about future corporate performance. To confront this issue, one may consider textual information that can transmit future corporate potential without any hysteresis. The key point is how to digest an extensive amount of textual information and identify those topics most likely to precede changes in operation status. Topic modeling can categorize these textual disclosures based on their underlying content and help examine which topics have a strong relevance to corporate operations. To extract decisive words from textual information, we set up a statistical-based approach with objectivity as opposed to frequently used heuristics (i.e., dictionary-based approaches with human involvement). Joint utilization of topic modelling and a statistical-based approach can compress an excessive amount of textual information into a manageable size in a timely manner and further realize a discrepancy among various topics in terms of relevance and influence on corporate operations. Our results benefit managers and current and future investors in how to structure regulatory filings and how word choices are decisive to them in their decision judgments.